Shâba‛ (שָׁבַע, Strong's #7650), “to swear; take an oath.” This is a common word throughout the history of the Hebrew language. The fact that it occurs more than 180 times in the Hebrew Bible attests to its importance there also. Shâba‛ occurs for the first time in the Hebrew Bible in Gen. 21:23-24, where Abimelech requests Abraham to “… swear unto me here by God that thou wilt not deal falsely with me, nor with my son.… And Abraham said, I will swear.”

Often “to swear or to take an oath” is to strongly affirm a promise. Thus, Joshua instructs the spies concerning Rahab of Jericho: “Go into the harlot’s house, and bring out thence the woman, and all that she hath, as ye sware unto her” (Josh. 6:22). David and Jonathan strongly affirmed their love for each other with an oath (1 Sam. 20:17). Allegiance to God is pledged by an oath (Isa. 19:18). Zephaniah condemns the idolatrous priests “that worship and that swear by the Lord, and that swear by Malcham [the Ammonite god]” (Zeph. 1:5). In making and upholding His promises to men, God often “swears” by Himself. To Abraham after his test involving His command to sacrifice his son Isaac, God said: “By myself have I sworn, saith the Lord, for because thou hast done this thing, and hast not withheld thy son, thine only son: That in blessing I will bless thee …” (Gen. 22:16-17; cf. Isa. 45:23; Jer. 22:5). God also “swears” by His holiness (Amos 4:2).

The root for “to swear” and the root for “seven” are the same in Hebrew, and since the number seven is the “perfect number,” some have conjectured that “to swear” is to somehow “seven oneself,” thus to bind oneself with seven things. Perhaps this is paralleled by the use of “seven” in Samson’s allowing himself to be bound by seven fresh bowstrings (Judg. 16:7) and weaving the seven locks of his head (Judg. 16:13). The relationship between “to swear” and “seven” is inconclusive.

Bibliography Information
Vines, W. E., M. A. Entry for 'Swear'. Vine's Expository Dictionary of OT Words. https://www.studylight.org/dictionaries/eng/vot/s/swear.html. 1940.

Bible Dictionaries Swear

Vine's Expository Dictionary of OT Words

Bible Dictionaries
Swear