Galatians 3:15-17 Living Bible (TLB)
15 Dear brothers, even in everyday life a promise made by one man to another, if it is written down and signed, cannot be changed. He cannot decide afterward to do something else instead.
16 Now, God gave some promises to Abraham and his Child. And notice that it doesn’t say the promises were to his children, as it would if all his sons—all the Jews—were being spoken of, but to his Child—and that, of course, means Christ. 17 Here’s what I am trying to say: God’s promise to save through faith—and God wrote this promise down and signed it—could not be canceled or changed four hundred and thirty years later when God gave the Ten Commandments.