Bible Commentaries
Isaiah 8

Introduction

Isaiah 8:0

PARAGRAPH DIVISIONS OF MODERN TRANSLATIONS

READING CYCLE THREE (see “Guide to Good Bible Reading”)

FOLLOWING THE ORIGINAL AUTHOR'S INTENT AT PARAGRAPH LEVEL

This is a study guide commentary, which means that you are responsible for your own interpretation of the Bible. Each of us must walk in the light we have. You, the Bible, and the Holy Spirit are priority in interpretation. You must not relinquish this to a commentator.

Read the chapter in one sitting. Identify the subjects (reading cycle #3). Compareyour subject divisions with the five translations above. Paragraphing is not inspired, but it is the key to following the original author's intent, which is the heart of interpretation. Every paragraph has one and only one subject.

1. First paragraph

2. Second paragraph

3. Third paragraph

4. Etc.

CONTEXTUAL INSIGHTS

A. This chapter illustrates the problem of trying to outline poetic prophecy by stanzas. It is unsure how these stanzas are structured. It is even unsure to whom they are spoken!

B. In chapters like this it is best to try to find the main truth of each stanza. Then see if there are any “key” repeated words or concepts. Be careful of pushing details into dogmatic or systematic theologies. Hebrew poetry is notoriously ambiguous. See Appendix One.

C. Ambiguity is characteristic of Hebrew Poetry and Prophecy. Exegesis of the details kills the artistry (word plays, parallelism) and often loses the meaning in the minutia. These stanzas were originally separate. They were designed to be heard! They were meant to have an immediate emotional impact! Only with time, prayer, and progressive revelation do the truths become clear!

D. Isa. 6-8 has many SINGULAR PRONOUNS. YHWH is addressing the prophet and he often addresses groups as collective.

WORD PHRASE STUDY

Verses 1-4

NASB (UPDATED) TEXT: Isaiah 8:1-4 1Then the LORD said to me, “Take for yourself a large tablet and write on it in ordinary letters: Swift is the booty, speedy is the prey. 2And I will take to Myself faithful witnesses for testimony, Uriah the priest and Zechariah the son of Jeberechiah.” 3So I approached the prophetess, and she conceived and gave birth to a son. Then the LORD said to me, “Name him Maher-shalal-hash-baz; 4for before the boy knows how to cry out 'My father' or 'My mother,' the wealth of Damascus and the spoil of Samaria will be carried away before the king of Assyria.”

Isaiah 8:1-4 Isaiah's second son (cf. Isaiah 8:3) is a prophecy about the destruction of Judah's main invader (i.e., Syro-Ephraimite war), Syria (capital of Damascus). Damascus was captured by Assyria in 732 B.C. and the inhabitants of the land were exiled. In some ways Isaiah's second son parallels the promised child of Isaiah 7:14-16.

Isaiah 8:1 “Take for yourself a large tablet and write on it” YHWH gives Isaiah two commands.

1. “take,” BDB 542, KB 534, Qal IMPERATIVE

2. “write,” BDB 507, KB 503, Qal IMPERATIVE, often used of an engraving tool, cf. Exodus 32:4, Exodus 32:16

Notice that what YHWH will reveal must be written for contemporary, as well as future, readers and that it will take a “large” (BDB 152) piece of writing material or clay tablet or seal (cf. Isaiah 30:8). The Hebrew word (BDB 163) does not designate what kind of material (notice its use in Isaiah 3:23, where it could refer to cylindrical seals worn around the neck, cf. JB footnote, p. 1155, and the IVP Bible Background Commentary, p. 594). It is not certain from the text if the message is long or that it is just a phrase written in large letters!

NASB“in ordinary letters” NKJV, LXX “with a man's pen” NRSV, REB, JPSOA“in common characters” TEV“in large letters” NJB“with an ordinary stylus” PESHITTA“on it plainly”

This is obviously an ambiguous phrase because it is the only place with this word for “man” (BDB 60) is used for an inanimate object. YHWH wants His message recorded so that all His people can easily understand His message.

NASB“Swift is the booty, speedy is the pray” NKJV, NRSV“Maher-shalal-hash-baz” TEV“Quick loot, fast plunder” PESHITTA“to hasten the captivity, and to record the spoil” JB footnote“Speed-spoil-quick-booty” REB footnote“Speedy for spoil, hastening for plunder”

This is the name of Isaiah's second son, “Maher-shalal-hash-baz” (cf. Isaiah 8:3). The same two VERBS are in the sarcastic statement of Isaiah 5:19. It may be YHWH's reaction to that Judean arrogance. It had (as all Isaiah's sons' names) a prophetic meaning for the people of his day. It seems to refer to Assyrian invasion because of Ahaz's unbelief. This invasion overwhelms Judah as well as Syria and Israel.

In Habakkuk 1:6-8 the same two VERBS describe the Babylonian invasion of Judah.

Isaiah 8:2

NASB“I will take to Myself” NKJV“I will take for Myself” NRSV“have it attested for me” NJB“take” LXX“make me” PESHITTA“I took to me” JB“find me” REB“I had it witnessed for me” JPSOA“call”

The VERB in the MT is “bear witness” (BDB 729, KB 795, Hiphil COHORTATIVE). The Dead Sea Scrolls, LXX, and Peshitta change the VERB to an IMPERATIVE and are followed by NRSV, REB. In context God is looking for two faithful witnesses (cf. Deuteronomy 4:26; Deuteronomy 30:19; Deuteronomy 31:28) to corroborate His message (i.e., heaven and earth, see note at Isaiah 1:2).

The first named witness, “Uriah the priest,” is mentioned in 2 Kings 16:10-16 (in a rather poor light). The other witness (Zechariah, son of Jeberechiah) is not known unless it refers to the Zechariah of Uzziah's day in 2 Chronicles 26:0.

The NIDOTTE, vol. 3, p. 336, thinks it is Isaiah himself who wants the two witnesses to be present when he names his second son.

Isaiah 8:3

NASB“I approached” NKJV, NRSV, LXX“I went to” NJB“I had intercourse with” REB“I lay with”

The VERB (BDB 897, KB 1132, Qal IMPERFECT) denotes sexual contact (cf. Genesis 20:4; Leviticus 18:6, Leviticus 18:14, Leviticus 18:19; Deuteronomy 22:14; Ezekiel 18:6).

Again the question of “who” is pregnant in Isaiah 7:14 arises. There are two main possibilities.

1. the special child reflects an ideal Davidic king and, therefore, probably Hezekiah, Ahaz's son

2. Isaiah may have been related to Ahaz, if so, his child could also be a Davidic king. The proximity of Isaiah 8:3 to 7:14 makes Isaiah's second child a possible “near term” fulfillment.

▣ “the prophetess” This is obviously a reference to Isaiah's wife. She was (1) also a prophet (BDB 612, FEMININE SINGULAR) or (2) was married to a prophet.

SPECIAL TOPIC: WOMEN IN THE BIBLE

Isaiah 8:4 This seems to parallel the time frame and message of Isaiah 7:15-16 (and Isaiah 8:4).

Isaiah's son's name depicts this very event by Assyria (cf. Isaiah 10:5-7).

Verses 5-8

NASB (UPDATED) TEXT: Isaiah 8:5-8 5Again the Lord spoke to me further, saying, 6”Inasmuch as these people have rejected the gently flowing waters of Shiloah And rejoice in Rezin and the son of Remaliah; 7Now therefore, behold, the Lord is about to bring on them the strong and abundant waters of the Euphrates, Even the king of Assyria and all his glory; And it will rise up over all its channels and go over all its banks. 8Then it will sweep on into Judah, it will overflow and pass through, It will reach even to the neck; And the spread of its wings will fill the breadth of your land, O Immanuel.”

Isaiah 8:5-6 This stanza continues the message of YHWH's judgment on Syria and Israel by Assyria, but adds the terrible results that will also affect Judah (i.e., Jerusalem spared, cf. Isaiah 8:8b). She will not be destroyed, but only barely survive.

Isaiah 8:6 “these people” To whom does this refer?

1. Israel

2. Judah

The answer is found in Isaiah 8:6b. Judah did not rejoice in Rezin, but Israel (“son of Remaliah”) made a political and military alliance with him (cf. Isaiah 7:4-5, Isaiah 7:8, Isaiah 7:9). Therefore, Isaiah 8:7 must refer to the destruction of not only Damascus (cf. Isaiah 7:20), but Samaria (i.e., Israel). It is possible it refers to a group within Judah who wanted to join the coalition.

Motyer, in Tyndale Old Testament Commentary Series (p. 81), notes that the phrase “this people” can refer to

1. Judah, Isaiah 28:14

2. a foreign power, Isaiah 23:13

3. Israel, Isaiah 9:16 (and here)

▣ “the gently flowing waters of Shiloh” This was a small wadi east of Jerusalem which carried the water from the spring Gihon into the city (cf. 2 Kings 20:20; 2 Chronicles 32:30). It is a symbol of (1) YHWH's neglected acts or words (cf. Isaiah 5:24; Isaiah 30:12) or (2) YHWH's provision for Jerusalem, the house of David, Judah, during a siege.

▣ “And rejoice in Rezin and the son of Remaliah” Syria was a part of the conspiracy to overthrow the throne of David (cf. Isaiah 7:6). Israel had put her trust in political and military alliances.

▣ “rejoice” This term (BDB 965) means “exult” or “rejoice,” which does not fit the context. It is possible that it was chosen to fit the poetry of the verse, not the dictionary. The VERBS “reject,” Isaiah 8:6 and “rejoice,” Isaiah 8:6, sound similarly. This prophecy would have been read aloud. There are several theories about who it refers to.

1. Damascus' joy

2. a group of Judeans who oppose Ahaz's Assyrian alliance

3. “melt” in fear, not rejoice (emendation)

4. Judah's joy at Assyria invading Syria and Israel

Obviously the context is uncertain as to whom it refers.

Isaiah 8:7 “the Lord is about to bring on them” YHWH is in control of history (cf. Isaiah 5:26; Isaiah 7:7, Isaiah 7:18; Isaiah 10:5; Isaiah 13:2-3). History is not random, but teleological. It has a terminus point. History moves by the consequences of human sin and the purposes of God!

▣ “waters of the Euphrates” This is one of the two main rivers of Mesopotamia. The Tigris and Euphrates formed a fertile crescent that reached from the Persian Gulf to close to the coast of the Mediterranean in Lebanon. A desert separated the empires of Mesopotamia (i.e., Assyria and Babylon) from Canaan. Therefore, the armies followed the waters of the Euphrates and moved down the coast lands of Lebanon and Canaan. This geographical route became the source of the biblical imagery of the “north” as the direction of evil.

Isaiah 8:8 This verse shows the consequences of an Assyrian takeover of Canaan. Judah will survive as a nation, but just barely. Ahaz did not listen to Isaiah, did not believe in YHWH's promises.

▣ “the spread of its wings will fill the breadth of your land” The NASB, NRSV, NJB, REB link this to the destruction caused by Assyria (“wing” used as a metaphor for “end,” cf. NIDOTTE, vol. 2, p. 670, thereby denoting the invasion of all the land), but TEV and JPSOA take the change of metaphor (i.e., from a flood to describe an Assyrian invasion) to the spreading of a bird's wings (BDB 642 CONSTRUCT BDB 489, cf. Isaiah 8:8; Psalms 17:8; Psalms 36:7; Psalms 57:1; Psalms 61:1, Psalms 61:4; Psalms 63:7; Psalms 91:1, Psalms 91:4) to relate to God's promised special child of Isaiah 7:14; also note Isaiah 8:9-10!

By noting that the promise was related to a conditional covenant which demanded faith and obedience. Without faith, Jerusalem's divine protection would send the wrong message (similar to people today seeing the state of Israel as a divine act of restoration, but the problem is she is not a faith-oriented or faithful-living covenant people)! Israel today is secular!

▣ “O Immanuel” The title here seems as if it refers to the Davidic king at the time (i.e., Ahaz). This may be a textual evidence that the child of Isaiah 7:14 was Hezekiah. Ultimately, it refers to Jesus, but in Isaiah it had to refer to a contemporary, naturally conceived male child (i.e., Isaiah 7:15-16)

Verses 9-10

NASB (UPDATED) TEXT: Isaiah 8:9-10 9”Be broken, O peoples, and be shattered; And give ear, all remote places of the earth. Gird yourselves, yet be shattered; Gird yourselves, yet be shattered. 10Devise a plan, but it will be thwarted; State a proposal, but it will not stand, For God is with us.”

Isaiah 8:9-10 The NASB of 1970 thought that verses Isaiah 8:9-15 were one stanza, but the NASB 1995 Update makes Isaiah 8:9-10 a separate stanza (I think rightly so, cf. NKJV, NRSV, Peshitta).

YHWH addresses the invading mercenary army.

1. be broken, Isaiah 8:9, BDB 949, KB 1270, Qal IMPERATIVE

2. be shattered, Isaiah 8:9, BDB 369, KB 365, Qal IMPERATIVE, cf. Isaiah 7:8; Isaiah 30:31; 1 Samuel 2:10; Jeremiah 48:1, Jeremiah 48:2; Jeremiah 49:37; Jeremiah 50:2; Jeremiah 51:56

3. give ear, Isaiah 8:9, BDB 24, KB 27, Hiphil IMPERATIVE

4-5. gird yourselves (twice), Isaiah 8:9, BDB 25, KB 28, Hithpael IMPERATIVE

6. be shattered, same as #2

7. devise a plan, Isaiah 8:10, BDB 734, KB 801, Qal IMPERATIVE

8. state a proposal, Isaiah 8:10, BDB 180, KB 210, Piel IMPERATIVE

For each action of the invaders there is an opposing plan of God. All their evil will come to naught. Now remember originally God called them to invade because of His people's sin, but after judgment God will again deliver His people so as to accomplish His purposes through them. See Special Topic at Isaiah 1:3.

Isaiah 8:10 “Devise a plan” This term (BDB 734) is used of human plans. Often these plans are different, even contrary, to YHWH's plans (cf. Isaiah 14:24-27; Proverbs 19:21). God will accomplish His plans (cf. Isaiah 46:10; Isaiah 55:8-11; Psalms 33:11). God needs nor seeks counselors (Isaiah 40:13). His plans are sure and eternal! He has a redemptive plan for all humans (see Special Topic: YHWH's Eternal Redemptive Plan).

▣ “For God is with us” This is the meaning of the name “Immanuel” from Isaiah 7:14; Isaiah 8:8. In this context this title refers to Ahaz (the Davidic King).

Verses 11-15

NASB (UPDATED) TEXT: Isaiah 8:11-15 11For thus the LORD spoke to me with mighty power and instructed me not to walk in the way of this people, saying, 12”You are not to say, 'It is a conspiracy!' In regard to all that this people call a conspiracy, And you are not to fear what they fear or be in dread of it. 13It is the LORD of hosts whom you should regard as holy. And He shall be your fear, And He shall be your dread. 14Then He shall become a sanctuary; But to both the houses of Israel, a stone to strike and a rock to stumble over, And a snare and a trap for the inhabitants of Jerusalem. 15Many will stumble over them, Then they will fall and be broken; They will even be snared and caught.”

Isaiah 8:11-15 This stanza is another message related to

1. YHWH's judgment on His own sinful people

2. YHWH's prophet is thinking and saying His thoughts, not those of his contemporaries or society

This stanza reflects the message to Ahaz in Isaiah 7:9, now widened to the whole community. It is a message of judgment that could have been faith/hope!

Isaiah 8:11

NASB“with mighty power” NKJV, LXX“with a strong hand”

“Hand” (BDB 388) is used often in an anthropomorphical sense (see Special Topic: God Described As Human [anthropomorphism]) to speak of God's actions within the world.

1. special metaphor of revelation, Isaiah 8:11; Jeremiah 15:17; Ezekiel 1:3; Ezekiel 3:14, Ezekiel 3:22; Ezekiel 8:1; Ezekiel 33:22; Ezekiel 37:1; Ezekiel 40:1

2. metaphor for deliverance from Egypt, Exodus 3:20; Exodus 6:1; Exodus 13:3; Exodus 14:31

3. metaphor for oath and/or judgment

a. swing His hand, Isaiah 19:16; Zechariah 2:9

b. lifts up His hand, Isaiah 26:11; Isaiah 49:22; Deuteronomy 32:40; Ezekiel 20:5

c. stretches out His hand, Isaiah 14:26-27; Exodus 7:5; Jeremiah 6:12

4. metaphor for creation, Isaiah 19:25; Isaiah 45:11-12; Isaiah 48:13; Isaiah 60:21; Isaiah 64:8

▣ “not to walk in the way of this people” Isaiah 8:11 is addressed to Isaiah, but Isaiah 8:12 is PLURAL. “Walk” is a metaphor for lifestyle (i.e., Psalms 1:6). God's people (of the Abrahamic covenant promise) were not God's people (in the Mosaic covenant obedience). They had become a corrupted witness to the nations (cf. Ezekiel 36:22-38).

In the new day, the day of the special child, a new way will be made available (cf. Isaiah 57:14; Isaiah 62:10). This is the concept John the Baptist saw as his mission (i.e., prepare the way, cf. Isaiah 40:3; Matthew 3:3; Mark 1:3; Luke 3:4-6).

Isaiah 8:12 This refers to Isaiah 7:2. They heard about the Syro-Ephraimite coalition and were terrified!

It is also possible that it refers to Isaiah's opposition to Ahaz's Assyrian alliance policy. The prophet would have been considered a troublemaker or worse, a traitor!

Isaiah 8:13 What they should have feared/awed was the holy LORD of hosts. He is the captain of the truly powerful army (cf. Isaiah 41:10, Isaiah 41:13, Isaiah 41:14; Isaiah 43:1, Isaiah 43:5; Isaiah 44:2; Isaiah 54:4). He is truly in control of events (cf. Isaiah 7:7, Isaiah 7:18, Isaiah 7:20).

There is no VERB with

1. He shall be your fear (BDB 432, or “let him be. . .”)

2. He shall be your dread (BDB 791, or “let him be. . .”)

This intensifies the phrases. There is an appropriate (cf. Psalms 76:12; Malachi 2:5) and inappropriate fear (cf. Luke 12:4; John 12:43)! To fear YHWH is wisdom (cf. Proverbs 1:7) and faithfulness; to fear human power is a lack of faith in YHWH's presence and promises!

Isaiah 8:14-15 YHWH describes His reaction to being rejected by His own covenant people with two metaphors of judgments.

1. a sanctuary (cf. Ezekiel 11:16) built of stones (YHWH was the sanctuary, cf. Ezekiel 11:16)

2. an animal snare and trap

His people, Israel (“both the houses of Israel”), will stumble over (BDB 505, KB 502, Qal PERFECT) the stones of the sanctuary. This metaphor is later developed into the rejected cornerstone (the Messiah). See Special Topic following.

Many of His people, Judah, will fall over (BDB 656, KB 709, Qal PERFECT) a stone or into a trap (i.e., pit) or be caught in a snare (cf. Isaiah 28:13) and perish (cf. Isaiah 24:18)! However, some (i.e., the faithful remnant), will trust in Him (cf. Isaiah 8:16-18).

SPECIAL TOPIC: CORNERSTONE

Verses 16-18

NASB (UPDATED) TEXT: Isaiah 8:16-18 16Bind up the testimony, seal the law among my disciples. 17And I will wait for the LORD who is hiding His face from the house of Jacob; I will even look eagerly for Him. 18Behold, I and the children whom the LORD has given me are for signs and wonders in Israel from the LORD of hosts, who dwells on Mount Zion.

Isaiah 8:16-18 This stanza links to the beginning of the chapter (cf. Isaiah 8:1-2). These prophetic messages are for YHWH's faithful disciples (in every age). There has been/always will be a group of faithful disciples (BDB 541). Isaiah uniquely uses this connotation (i.e., disciples) of this term (cf. Isaiah 8:16; Isaiah 50:4 [twice]; Isaiah 54:13), usually translated “teach,” “train,” “learn.”

Who then does Isaiah 8:19-22 describe? It could refer to (1) faithless Judeans (i.e., Southern Kingdom) or (2) faithless Israelites (i.e., the Northern Kingdom).

Isaiah 8:16 Isaiah is to

1. bind, BDB 864, KB 1058, Qal IMPERATIVE

2. seal, BDB 367, KB 364, Qal IMPERATIVE (i.e., put a wax seal on the outer edge)

These are metaphors denoting preservation and security!

Isaiah 8:17 Isaiah speaks on behalf of the faithful remnant during times of divine punishment. They will “wait” (BDB 314, KB 313, Piel PERFECT), which can also mean “hope,” “wait patiently,” or “long for,” usually used of hoping/waiting for God (Isaiah 8:17; Isaiah 25:9; Isaiah 26:8; Isaiah 33:2; Isaiah 40:31; Isaiah 51:5; Isaiah 60:9; Isaiah 64:4; Zephaniah 3:8). Faith is expressed by patience and hope through trials and the passing of time.

▣ “the LORD who is hiding His face” This is a metaphor for a broken relationship (cf. Deuteronomy 31:17-18).

▣ “I will even look eagerly for Him” This VERB (BDB 875, KB 1082, Piel PERFECT) denotes intense longing.

1. used of YHWH in Isaiah 5:2, Isaiah 5:7

2. used of His disciples in Isaiah 25:9; Isaiah 33:2; Isaiah 60:9

This stresses the interpersonal aspect of faith. It is not God's blessings, but His presence that believers ultimately desire! This is what the title “Immanuel” implies.

Isaiah 8:18 This refers in context to Isaiah in the eighth century, but ultimately it applies best to Jesus (cf. Hebrews 2:13).

▣ “who dwells on Mount Zion” In reality YHWH dwelt in heaven, but the Ark of the Covenant was His footstool (i.e., cf. 1 Chronicles 28:2; Psalms 99:5; Psalms 132:7, the place where heaven and earth met).

Verses 19-22

NASB (UPDATED) TEXT: Isaiah 8:19-22 19When they say to you, “Consult the mediums and the spiritists who whisper and mutter,” should not a people consult their God? Should they consult the dead on behalf of the living? 20To the law and to the testimony! If they do not speak according to this word, it is because they have no dawn. 21They will pass through the land hard-pressed and famished, and it will turn out that when they are hungry, they will be enraged and curse their king and their God as they face upward. 22Then they will look to the earth, and behold, distress and darkness, the gloom of anguish; and they will be driven away into darkness.

Isaiah 8:19-22 This prose paragraph contrasts the false faith involved in seeking mediums and wizards with the true faith of trusting in and seeking YHWH. The prohibitions against mediums and wizards are found in Deuteronomy 18:9-11 and Leviticus 20:26, 31.

Isaiah 8:19 “Consult” This VERB (BDB 205, KB 233) is used twice in this verse.

1. seek, consult, inquire of false gods (occult), Qal IMPERATIVE

2. seek, consult, inquire of YHWH, Qal IMPERFECT

In Isaiah 11:10 this same VERB is used of the nations coming to the root of Jesse (i.e., the Davidic Messiah).

YHWH's hand was on Isaiah in Isaiah 8:11, but these false prophets spoke from their own imagination or demonic influence. What a contrast between the true speaker and false speakers. Yet, fallen humans flock to false teachers!

▣ Notice the lists of occultic practices that God's people had assimilated from the surrounding nations.

1. mediums, The PARTICIPLE's (BDB 981, KB 1371) basic meaning is to “ask” or “inquire.”

Here to inquire of the spirit realm (e.g., YHWH, Joshua 9:14 or idols, Hosea 4:12).

The first NOUN, “medium” (BDB 15) is a difficult term to define. Some see the term as it is used in Leviticus 19:31; Leviticus 20:6, Leviticus 20:27 as (1) a pit or grave where spirits are lured, (2) form of “father” which refers to ancestor worship. It is translated in the LXX in Isaiah 8:19 as “ventriloquist.” Because of this and Isaiah 29:4 some think it means “to chirp” or “to mutter.” This would imply to “talk with a different voice.” However, from 1 Samuel 28:7-9, it is related to the ability to call or talk to someone in the ground or to communicate with the dead or spirits of the underworld, i.e., necromancy.

The second NOUN, “spiritists” (BDB 396) was a form of the Hebrew word “to know” (BDB 395). It refers to one who has knowledge of the spiritual realm or has contact with those in the spiritual realm who have knowledge (cf. Isaiah 8:19; Isaiah 19:3).

2. spiritists, This (BDB 396) is the term describing males with familiar spirits who communicate with the dead (cf. Isaiah 19:3; Leviticus 19:31; Leviticus 20:6, Leviticus 20:27; Deuteronomy 18:11; 1 Samuel 28:3, 1 Samuel 28:9; 2 Kings 21:6; 2 Kings 23:24

a. they whisper, BDB 861, KB 1050, Pilpel PARTICIPLE, cf. Isaiah 29:4

b. they mutter, BDB 211, KB 237, Hiphil PARTICIPLE

Isaiah 8:20 “To the law and to the testimony” The NRSV and REB translations see this phrase as finishing the sentence begun in Isaiah 8:19. God's people are to seek Him (i.e., Isaiah 19:3; Isaiah 31:1) and His word, not the dead, for truth and life!

But false speakers cannot know truth because they have no light (“dawn,” cf. Isaiah 47:12-13). God has provided His prophets, His message, His written record (cf. Isaiah 8:1, Isaiah 8:2, Isaiah 8:16).

Isaiah 8:21 “they” Literally all the VERBS in Isaiah 8:21 and 22 are SINGULAR, cf. NJB. This refers to the covenant people. They seek knowledge in false religions and wonder why their gods cannot produce prosperity. Prosperity is one of the covenant promises of Deuteronomy 27-28, but it is inseparably related to covenant fidelity!

In the end (i.e., the results of agricultural judgment, cf. Isaiah 8:22; Isaiah 5:13-17) they will speak evil of the civic leaders and their false gods (cf. NRSV and REB, which follow LXX).

It is possible that speaking evil is an allusion to Exodus 22:28 and Leviticus 24:15-16. If so, then it is another example of covenant violations. For me the context of Isaiah 8:19-20 links it to false gods.

Isaiah 8:22 This verses goes with Isaiah 9:0. The context is a play between gloom/darkness and light. Notice the parallel in Isaiah 5:30. This was the opposite of YHWH's initial creative purposes (cf. Jeremiah 4:23-26, Jeremiah 4:27-28).