15 My friends, I will use an everyday example to explain what I mean. Once someone agrees to something, no one else can change or cancel the agreement.
16 That is how it is with the promises God made to Abraham and his descendant. The promises were not made to many descendants, but only to one, and that one is Christ.
17 What I am saying is that the Law cannot change or cancel God's promise that was made 430 years before the Law was given.
18 If we have to obey the Law in order to receive God's blessings, those blessings don't really come to us because of God's promise. But God was kind to Abraham and made him a promise.
19 What is the use of the Law? It was given later to show that we sin. But it was only supposed to last until the coming of that descendant who was given the promise. In fact, angels gave the Law to Moses, and he gave it to the people.
20 There is only one God, and the Law did not come directly from him.
21 Does the Law disagree with God's promises? No, it doesn't! If any law could give life to us, we could become acceptable to God by obeying that law.