“Again, you have heard that it was said to the people long ago, ‘Do not break your oath, but fulfill to the Lord the vows you have made.’ But I tell you, do not swear an oath at all: either by heaven, for it is God’s throne; or by the earth, for it is his footstool; or by Jerusalem, for it is the city of the Great King. And do not swear by your head, for you cannot make even one hair white or black. All you need to say is simply ‘Yes’ or ‘No’; anything beyond this comes from the evil one.
It was the Jewish custom to swear an oath to ensure that a person would keep his word in making a promise. This was not something that God was crazy about; rather it was more of a divine concession to the reality of our fallen state in this world when it came to the provisions for oaths in the Law. It was though a person was admitting that what he said may or may not true, unless he “swore”, much like it was among the boys I knew as a child; if I “swear” it’s true, then I must be really serious, but if I didn’t “swear it” it might be a lie.
Jesus wants no part of this kind of thinking in the Kingdom; everything we say is to be true; there is no place whatsoever for falsehood as a follower of Christ, so there will be no “swearing” necessary. More than anything else, these verses call all of us to be men and women of integrity and faithfulness, as God is integrity and faithfulness.
I wonder what things would look like in the here and now if we took this injunction to heart!