Matthew 5:33

“Again, ye have heard that it hath been said, etc.] Besides what has been observed, in ver. 21 and 27 you know it has also been said, by, or to them of old time, what is written in (<031912>Leviticus 19:12). “And ye shall not swear by my name falsely”; which seems to be referred to, when it is said, “thou shalt not forswear thyself”: and is the law forbidding perjury, or false swearing; and was what the Jews were chiefly, if not only concerned about; little regarding the vanity, only the truth of an oath: for they took swearing vainly, to be the same as swearing falsely; wherefore so long as what they swore was truth, they were not careful whether it was of any importance or not: moreover,…”

“Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself--These are not the precise words of Exo 20:7; but they express all that it was currently understood to condemn, namely, false swearing (Lev 19:12, &c.). This is plain from what follows. But I say unto you, Swear not at all--That this was meant to condemn swearing of every kind and on every occasion--as the Society of Friends and some other ultra-moralists allege--is not for a moment to be thought. For even Jehovah is said once and again to have sworn by Himself; and our Lord certainly answered upon oath to a question put to Him by the high priest; and the apostle several times, and in the most…”

“Thou shalt not forswear thyself - Christ here proceeds to correct another false interpretation of the law. The law respecting oaths is found in Leviticus 19:12, and Deuteronomy 23:23. By those laws people were forbid to perjure themselves, or to forswear, that is, swear falsely. Perform unto the Lord - Perform literally, really, and religiously what is promised in an oath. Thine oaths - An oath is a solemn affirmation or declaration, made with an appeal to God for the truth of what is affirmed, and imprecating his vengeance, and renouncing his favor if what is affirmed is false. A false oath is called perjury, or, as in this place, forswearing. It appears, however, from this passage, as well…”

“Our Lord here refers to the promise made to the pure in heart of seeing God in all things, and points out a false doctrine of the scribes, which arose from their not thus seeing God. What he forbids is, the swearing at all, by any creature, in our ordinary conversation: both of which the scribes and Pharisees taught to be perfectly innocent. Exo 20:7. Matthew 5:36”

“5:33-37 Jesus here summarizes the Old Testament teaching on oaths (Lev 19:12; Num 30:2-4; Deut 23:21-23; Ps 50:14; Zech 8:17). The Pharisees had degrees of commitment for oaths—for example, ones that did not mention God were not as binding. Jesus shows that because God is related to all things (heaven, earth, Jerusalem, my head; see also Matt 23:16-22), breaking any oath breaks God’s command (see Exod 20:7). The point is that one must be altogether truthful. Jesus’ righteousness elevates the disciple’s everyday yes and no to the level of binding oath. Oaths become superfluous to the honest person (Jas 5:12).”

“it hath: Mat 23:16 Thou: Exo 20:7; Lev 19:12; Num 30:2-16; Deu 5:11, Deu 23:23; Psa 50:14, Psa 76:11; Ecc 5:4-6; Nah 1:15 Matthew 5:34”