The oaths of the Pharisees
But how far they were from seeing God, who, having heard that it had been said by those of old, You shall not swear falsely, but shall perform to the Lord your oaths (Matthew 5:33), interpreted it this way: You shall not swear falsely when you swear by the Lord Jehovah. You shall perform to the Lord these oaths of yours. But as for other oaths, he does not regard them.
So the Pharisees taught. They not only allowed every kind of swearing in common conversation, but counted even false swearing a small thing, so long as they had not sworn by the special name of God.
1771 text
9. But how far were they from seeing God, who having heard, that it had been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: interpreted it thus, Thou shalt not forswear thyself, when thou swearest by the Lord Jehovah. Thou shalt perform unto the Lord these thine oaths. But as to other oaths, he regardeth them not.
So the Pharisees taught. They not only allowed all manner of swearing in common conversation: but accounted even forswearing a little thing, so they had not sworn by the peculiar name of God.