Charles Spurgeon Commentary Matthew 5:33-34

"Again, ye have heard that it was said to them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: but I say unto you, swear not at all; neither by the heaven, for it is the throne of God;" — Matthew 5:33-34 (ASV)

Again, you have heard that it has been said by them of old time, You shall not forswear yourself, but shall perform to the Lord your oaths: but I say to you, Do not swear at all.

Christ thus abolishes the whole system of swearing, as it ought to be abolished in every place; and he goes on to show that he did not mean merely unclean, false oaths, or oaths taken blasphemously by some men, but every form and kind of oath, for he says, Do not swear at all.