Oath

 A solemn appeal to God, permitted on fitting occasions De 6:13
 Jer 4:2 in various forms Ge 16:5 2Sa 12:5 Ru 1:17 Ho 4:15
 Ro 1:9 and taken in different ways Ge 14:22 24:2 2Ch 6:22
 God is represented as taking an oath Heb 6:16-18 so also Paul 
 Ro 9:1 Ga 1:20 Php 1:8 The precept, "Swear not at all," refers 
 probably to ordinary conversation between man and man Mt 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."