Expositor's Bible Commentary Commentary Matthew 5:36

"Neither shalt thou swear by thy head, for thou canst not make one hair white or black." — Matthew 5:36 (ASV)

Jesus now cites an antithesis on a new theme. What the people have heard is not given as direct OT quotation but as a summary statement accurately condensing the burden of Ex 20:7; Leviticus 19:12; Numbers 30:2; and Dt 5:11; 6:3; 22:21–33. The Mosaic law forbade irreverent oaths, light use of the Lord’s name, and broken vows. Once the Lord’s name was invoked, the vow to which it was attached became a debt that had to be paid to the Lord (see comments on 23:16– 22).

If oaths designed to encourage truthfulness become occasions for clever lies and casuistical deceit, Jesus will abolish oaths (v.34). For the direction in which the OT points is the fundamental importance of thorough and consistent truthfulness. If one does not swear at all, one does not swear falsely. Jesus insists that whatever anyone swears by is related to God in some way, and therefore every oath is implicitly in God’s name—heaven, earth, Jerusalem, even the hairs of the head are all under God’s sway and ownership (v.36).