Galatians 3:15
Brothers, let me take an example from everyday life. Just as no one can set aside or add to a human covenant that has been duly established, so it is in this case. — Paul's legal analogy: a duly ratified covenant ('diathēkē' — covenant/testament, from the secular domain) cannot be unilaterally altered; this principle governs even God's covenants, establishing the Abrahamic covenant's permanence and inviolability.