34 But I say to you, Do not swear at all, either by heaven, for it is the throne of God, 35 or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King. 36 And do not swear by your head, for you cannot make one hair white or black. 37 Let your word be "Yes, Yes' or "No, No'; anything more than this comes from the evil one.
Matthew Henry's Commentary on Matthew 5:34-37
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.