33 "You have also heard that our ancestors were told, 'You must not break your vows; you must carry out the vows you make to the Lord.' 34 But I say, do not make any vows! Do not say, 'By heaven!' because heaven is God's throne. 35 And do not say, 'By the earth!' because the earth is his footstool. And do not say, 'By Jerusalem!' for Jerusalem is the city of the great King. 36 Do not even say, 'By my head!' for you can't turn one hair white or black. 37 Just say a simple, 'Yes, I will,' or 'No, I won't.' Anything beyond this is from the evil one.
Matthew Henry's Commentary on Matthew 5:33-37
Commentary on Matthew 5:33-37
(Read Matthew 5:33-37)
There is no reason to consider that solemn oaths in a court of justice, or on other proper occasions, are wrong, provided they are taken with due reverence. But all oaths taken without necessity, or in common conversation, must be sinful, as well as all those expressions which are appeals to God, though persons think thereby to evade the guilt of swearing. The worse men are, the less they are bound by oaths; the better they are, the less there is need for them. Our Lord does not enjoin the precise terms wherein we are to affirm or deny, but such a constant regard to truth as would render oaths unnecessary.