2 Bible Verses about Covenant Obligations

"Again, you have heard that the men of old were told, 'You shall not swear falsely, but you must fulfil your oaths to the Lord.' But I tell you not to swear 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.read more.
You must not swear by your own head, for you cannot make one single hair white or black. But your way of speaking must be 'Yes' or 'No.' Anything that goes beyond that comes from the evil one.

To take an illustration, brothers, from daily life: even a human agreement, once ratified, no one annuls or alters.