83 Having, therefore, previously spoken of the existence of God, and also of the honour to be paid to the everlasting God; he then, following the natural order of connection proceeds to command what is becoming in respect of his name; for the errors of men with respect to this point are manifold and various, and assume many different characters. 84 That being which is the most beautiful, and the most beneficial to human life, and suitable to rational nature, swears not itself, because truth on every point is so innate within him that his bare word is accounted an oath. Next to not swearing at all, the second best thing is to keep one's oath; for by the mere fact of swearing at all, the swearer shows that there is some suspicion of his not being trustworthy.85 Let a man, therefore, be dilatory, and slow if there is any chance that by delay he may be able to avoid the necessity of taking an oath at all; but if necessity compels him to swear, then he must consider with no superficial attention, every one of the subjects, or parts of the subject, before him; for it is not a matter of slight importance, though from its frequency it is not regarded as it ought to be.
Date: 20-50 C.E. (based on scholarly estimates)
30 If your right hand causes you to sin, cut it off and throw it away! It is better to lose one of your members than to have your whole body go into hell. 31 “It was said, ‘Whoever divorces his wife must give her a legal document.’ 32 But I say to you that everyone who divorces his wife, except for immorality, makes her commit adultery, and whoever marries a divorced woman commits adultery. 33 “Again, you have heard that it was said to an older generation, ‘Do not break an oath, but fulfill your vows to the Lord.’ 34But I say to you, do not take oaths at all—not by heaven, because it is the throne of God, 35 not by earth because it is his footstool, and not by Jerusalem, because it is the city of the great King. 36 Do not take an oath by your head because you are not able to make one hair white or black.