Note 17 at Mt. 23:20: In the Hebrew way of thinking, an oath was a solemn appeal to the truth of an affirmation or promise. Invoking God's name in an oath carried the idea of the all- knowing, all-seeing God watching over men's words with the most serious consequences for those who broke them (Gen. 31:49-53; 1 Sam. 12:5; 19:6). The apostle Paul uses the same kind of Hebrew thinking as he calls upon God as a witness to the truthfulness of his statements (2 Cor. 1:23; Gal. 1:20; Phil. 1:8).

The law of Moses established guidance concerning oaths in several situations; (1) in the loss of one's personal property (Ex. 22:10-11), (2) in the finding of lost possessions (Lev. 6:3), (3) when a woman is suspected of unfaithfulness to her husband (Num. 5:11-31), (4) and in the misuse of swearing and concealing the truth (Lev. 5:1). The Old Testament also cautioned against swearing lightly with the solemn warning of Ecclesiastes 5:5: "Better is it that thou shouldest not vow, than that thou shouldest vow and not pay."

Although Jesus accepted the credibility of a claim confirmed by an oath (Mt. 26:63-64), His teaching denounced a double standard accepted by some Jews that one's word had to be confirmed by an oath. For Christ's followers, one's life and word should be as sacred as his oaths (Mt. 5:37). Under His rule, oaths should be an unnecessary thing (Mt. 5:34-37), for Christians carry Christ's name in all that they say and do (1 Cor. 6:20).