Matthew 5:33-34, 37
Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform your oaths to the Lord.’ But I say to you, do not swear at all: neither by heaven, for it is God’s throne; But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ For whatever is more than these is from the evil one.
by faith 