“Again you have heard that it was said to those who lived long ago: Don't make a false solemn pledge, but you should follow through on what you have pledged to the Lord.
References for Matthew 5:33
But I say to you that you must not pledge at all. You must not pledge by heaven, because it's God's throne.
You must not pledge by the earth, because it's God's footstool. You must not pledge by Jerusalem, because it's the city of the great king.
And you must not pledge by your head, because you can't turn one hair white or black.
Let your yes mean yes, and your no mean no. Anything more than this comes from the evil one.