Oath: a solemn appeal to God, permitted on fitting occasions (Deut.
6:13; Jer. 4:2), in various forms (Gen. 16:5; 2 Sam. 12:5; Ruth
1:17; Hos. 4:15; Rom. 1:9), and taken in different ways (Gen.
14:22; 24:2; 2 Chr. 6:22). God is represented as taking an oath
(Heb. 6:16-18), so also Christ (Matt. 26:64), and Paul (Rom.
9:1; Gal. 1:20; Phil. 1:8). The precept, "Swear not at all,"
refers probably to ordinary conversation between man and man
(Matt. 5:34,37). But if the words are taken as referring to
oaths, then their intention may have been to show "that the
proper state of Christians is to require no oaths; that when
evil is expelled from among them every yea and nay will be as
decisive as an oath, every promise as binding as a vow."