oath
a solemn appeal to God, permitted on fitting occasions (Deuteronomy 6:13; Jeremiah 4:2), in various forms (Genesis 16:5; 2 Samuel 12:5; Ruth 1:17; Hos. 4:15; Romans 1:9), and taken in different ways (Genesis 14:22; 24:2; 2 Chronicles 6:22)
God is represented as taking an oath (Hebrews 6:16-18), so also Christ (Matthew 26:64), and Paul (Romans 9:1; Galatians 1:20).
The precept, “Swear not at all,” refers probably to ordinary conversation between man and man (Matthew 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.”
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