Bible Commentaries
Genesis 21

Verses 1-7

Isaac Is Born

The son of the promise, the heir, is born “at the appointed time” (Genesis 21:2). God has the right time for everything (Ecclesiastes 3:1). Isaac is a picture of the Lord Jesus, as Abraham is of God the Father. The birth of Isaac is a picture of the introduction of the Firstborn, the Lord Jesus, by God into the world (Hebrews 1:6). God has “put all things in subjection under his feet” (Hebrews 2:8), He is the true Heir.

An application for our personal lives is that the Lord Jesus can only be “born” in our lives, which means become visible, when the Philistine influences we saw in the previous chapter have been discarded.

Abraham calls his son “Isaac”, as God has said to him (Genesis 17:19). “Isaac” means “laughter” (cf. Psalms 126:2). Isaac brings joy to Abraham’s family. Thus the Lord Jesus will always give us His joy when He is central to our lives.

By circumcising his son, Abraham places him under the covenant God has made with him and his physical descendants (Genesis 17:1-2 Chronicles :). For us Christians, circumcision is a picture of what happened to Christ on the cross (Colossians 2:11). Our life as a Christian is only valuable to God if we live from the meaning of the cross. There is the old man crucified with Christ (Romans 6:6). This allows us to keep ourselves dead for sin and alive for God in Christ Jesus (Romans 6:11).

Sarah recognizes the good hand of God over her life. He has made her son’s name, laughter, a reality for her. She also speaks of her joy being shared by all who will hear of it (cf. Luke 1:58). Others will rejoice in this example of God’s power and goodness and will be encouraged to trust in Him (Psalms 119:74).

At the same time, she expressed her surprise that God was so good for her. Who has ever been able to think that? This wonder about granted grace must also characterize our lives. Why were we chosen by Him to be His children and to rejoice in the Son of His love? It can only be attributed to God’s infinite love.

Verses 8-21

Abraham Drives out Hagar and Ishmael

After the circumcision comes the phase that starts with being weaned. This indicates that Isaac is becoming independent. He is no longer dependent on his mother’s food, but is now able to take food himself. Herein he also is a picture of the believer who grows towards spiritual independence in order to grow further as an independent believer.

This does not mean that growth takes place separately from others, but from a personal relationship with the Lord. In this growth the help of others will be very much appreciated. Therefore the church is also compared with a body that God has composed in such a way that “the members may have the same care for one another” (1 Corinthians 12:25).

For faith, this growth is a reason for a celebration. For the law, of which Ishmael is a picture, this is not so. He makes a mockery of it. That Ishmael is a picture of the law and of people who place themselves under the law and want to live accordingly, we see in Galatians 4, where Paul says: “Tell me, you who want to be under law, do you not listen to the law? For it is written that Abraham had two sons, one by the bondwoman and one by the free woman. But the son by the bondwoman was born according to the flesh, and the son by the free woman through the promise. This is allegorically speaking, for these [women] are two covenants: one [proceeding] from Mount Sinai bearing children who are to be slaves; she is Hagar. Now this Hagar is Mount Sinai in Arabia and corresponds to the present Jerusalem, for she is in slavery with her children. But the Jerusalem above is free; she is our mother. For it is written, “Rejoice, barren woman who does not bear; Break forth and shout, you who are not in labor; For more numerous are the children of the desolate Than of the one who has a husband.” And you brethren, like Isaac, are children of promise. But as at that time he who was born according to the flesh persecuted him [who was born] according to the Spirit, so it is now also. But what does the Scripture say? “Cast out the bondwoman and her son, For the son of the bondwoman shall not be an heir with the son of the free woman.” So then, brethren, we are not children of a bondwoman, but of the free woman” (Galatians 4:21-Obadiah :).

In this section Paul refers to Isaac and Ishmael and their mothers. He does not mention their names. It is not about their names, but about their positions, because the mothers transfer them to their children. After exposing the position, he points to the origins of both sons. Ishmael is born by Abraham’s own will, but Isaac he receives by a promise from God. The spiritual lessons to be learned by the Galatians and by us are clearly shown in that section.

At the end of that section we see the meaning of expelling Ishmael. That meaning is that what is born after the flesh always persecutes what is born after the Spirit (Galatians 4:29). Whoever is according to the Spirit and wants to live consistently according to it, will experience persecution from the side of people who want to serve God in their own power. Prosecution is inevitable, because living by faith is one great indictment of any form of religion that highlights one’s own performance.

He who wants to live according to the law, thinks of the things of the flesh and “the mind set on the flesh is hostile toward God” (Romans 8:7). There is no connection between the flesh and the law on the one hand and the Spirit on the other. Nothing comes from the flesh that can be recognized and accepted and blessed by God. For Abraham all blessings are bound with the son of the promise. In him the offspring is promised and only that offspring receives the promised blessing (Romans 9:7; Hebrews 11:18). Thus, for man, the blessing of God is linked to faith in Christ, the Son of promise. Unbelief, the flesh, has no part in this.

Therefore Paul concludes the explanation of this history as follows: “But what does the Scripture say? “Cast out the bondwoman and her son, For the son of the bondwoman shall not be an heir with the son of the free woman” (Galatians 4:30). The blessing of God can never be obtained through a kind of cooperation of law with grace. Everything that has to do with the law must disappear from the Christian’s life and thought.

It is a hard lesson to acknowledge that there is no place for the flesh. Abraham thinks so too. He does not want to drive out Hagar and Ishmael. God Himself must be involved to convince him of the correctness of Sarah’s decision. Then there is no more delay and Abraham sends Hagar and Ishmael away, after having provided them with the needs for the way.

Hagar represents the law (Galatians 4:24-Lamentations :). Her son Ishmael is a picture of Israel under the law. This people, who have no connection with the Son of promise, and even mocked and rejected Him, wander, as Hagar and Ishmael wander. But God is going His way with those people.

God hears the voice of the boy. We do not read that Ishmael has spoken a word to God, but he will have cried with his mother, and God has heard this loud crying. The place where he cries is near a well in the desert “Beersheba”. ‘Beersheba’ means ‘well of the oath’. So will God listen to his people when they mourn for the Firstborn, when they see the One Whom they have pierced (Zechariah 12:10).

Hagar is instructed to lift her son up and hold her hand well. God’s gracious intervention does not mean that man has nothing more to do. She is also promised that her son will become a great nation. After these words, God opens sources of provisions she has not seen before.

Verses 22-34

Abraham and Abimelech

Here the relationship between Abraham and Abimelech is completely reversed in comparison with the previous chapter. Abimelech acknowledges that God is with Abraham. This is a picture of what the nations will say in the future, when Israel has become the head of the nations (Zechariah 8:23).

A Christian can already get this recognition. If a Christian walks faithfully with God, it will be noticed. This is the result of the ‘driving out’ of the flesh, of not walking as the nations do. When Isaac – in our life: the Lord Jesus – gets its true place, this recognition comes from Abimelech – for us: from the world. However, Abraham is painfully reminded of his failure (Genesis 21:23).

Yet, as has been said, the relationship is completely different. Now Abraham reprimands Abimelech for a well and gives gifts to Abimelech. The well is named after the desert Beersheba. The covenant they make with each other is reinforced by a gift from Abraham’s hand. After this Abimelech returns to his country.

Abraham calls upon “the name of the LORD, the Everlasting God”. He expresses the awareness that God is beyond time and that all His promises will be fulfilled, even if there is nothing to be seen yet. That’s why in this belief he plants a tamarisk near Beersheba (‘well of the oath’). With this he indicates, as it were, the border between himself and the Philistines.