A solemn affirmation accompanied by an appeal to the Supreme Being. God has prohibited all false oaths, and all useless and customary swearing in ordinary discourse; but when the necessity or importance of a matter requires an oath, he allows men to swear by his name, Exodus 22:11 Leviticus 5:1. To swear by a false god was an act of idolatry, Jeremiah 5:7 12:16.
Among the Hebrews an oath was administered by the judge, who stood up, and adjured the party who was to be sworn. In this manner our Lord was adjured by Caiaphas, Matthew 26:63. Jesus had remained silent under long examination, when the high priest, rising up, knowing he had a sure mode of obtaining an answer said, "I adjure thee by the living God, that thou tell us whether thou be the Christ." To this oath, thus solemnly administered, Jesus replied that he was indeed the Messiah.
An oath is a solemn appeal to God, as to an all-seeing witness that what we say is true, and an almighty avenger if what we say be false, Hebrews 6:16. Its force depends upon our conviction of the infinite justice of God; that he will not hold those guiltless who take his name in vain; and that the loss of his favor immeasurable outweighs all that could be gained by false witness. It is an act of religious worship; on which account God requires it to be taken in his name, Deuteronomy 10:20, and points out the manner in which it ought to be administered, and the duty of the person who swears, Exodus 22:11 Deuteronomy 6:18 Psalms 15:4 24:4. Hence atheists, who profess to believe that there is no God, and persons who do not believe in a future state of reward and punishment, cannot consistently take an oath. In their mouths an oath can be only profane mockery.
God himself is represented as confirming his promise by oath, and thus conforming to what is practiced among men, Hebrews 6:13,16-17. The oaths forbidden in Matthew 5:34-35 James 5:12, must refer to the unthinking, hasty, and vicious practices of the Jews; otherwise Paul would have acted against the command of Christ, Romans 1:9 Galatians 1:20 2 Corinthians 1:23. That person is obliged to take an oath whose duty requires him to declare the truth in the most solemn and judicial manner; though undoubtedly oaths are too often administered unnecessarily and irreverently, and taken with but slight consciousness of the responsibility thus assumed. As we are bound to manifest every possible degree of reverence towards God, the greatest care is to be taken that we swear neither rashly nor negligently in making promises. To neglect performance is perjury, unless the promise be contrary to the law of nature and of God; in which case no oath is binding. See CORBAN, and
A customary formula of taking an oath was "The Lord do so to me, and more also;" that is, the lord slay me, as the victim sacrificed on many such occasions was slain, and punish me even more than this, if I speak not the truth, Ruth 1:17 1 Samuel 3:17. Similar phrases are these: "As the Lord liveth," Judges 8:19 "Before God I lie not," Romans 9:1; "I say the truth in Christ," 1 Timothy 2:7; "God is my record," Philippians 1.8. Several acts are alluded to as accompaniments of an oath; as putting the hand under the thigh, Genesis 24:2 47:29; and raising the hand towards heaven, Genesis 14:22,23 Deuteronomy 32:40 Revelation 10:5.
These dictionary topics are from American Tract Society Bible Dictionary published in 1859. Public Domain, copy freely.