(36) By thy head.--This is apparently chosen as an extreme instance of a common oath in which men found no reference to God. Yet here, too, nothing but an implied reference to Him fits it to be an oath at all. He made us, and not we ourselves, and the hairs of our head are not only numbered, but are subject in all their changes to His laws, and not to our volition.

Verse 36. - For thou canst not, etc. As each of the other objects included a reference to God, so does also thy head. For even that recalls to mind the power of God, since every hair of it bears the stamp of his handiwork.

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.Neither shalt thou swear by thy head,.... This also was a common form of swearing among the Jews: take a few instances.

"If anyone is bound to his friend by an oath, and says to him, vow unto me , "by the life of thy head"; R. Meir says (u), he may retract it; but the wise men say, he cannot.''

Again (w), a certain Rabbi said to Elijah,

"I heard "Bath Kol" (or the voice from heaven) mourning like a dove, and saying, woe to my children; for, because of their sins, I have destroyed my house, and have burnt my temple, and have carried them captive among the nations: and he (Elijah) said unto him , "by thy life, and by the life of thy head", not this time only it says so, but it says so three times every day.''

Once more (x), says R. Simeon ben Antipatras, to R. Joshua,

"I have heard from the mouth of the wise men, that he that vows in the law, and transgresses, is to be beaten with forty stripes: he replies, blessed art thou of God, that thou hast so done, , "by thy life, and by the life of thy head", he that is used to do so is to be beaten.''

This form of swearing is condemned, for this reason,

because thou canst not make one hair white or black: which shows, that a man's head, nor, indeed, one hair of his head, is in his own power, and therefore he ought not to swear by it; as he ought not to swear by heaven, or earth, or Jerusalem, because these were in the possession of God. Some copies read, "canst not make one white hair black".

(u) Misn. Sanhedrim, c. 3. sect 2.((w) T. Bab. Beracot, fol. 3. 1. (x) Derech. Eretz, c. 6. fol. 18. 2.