But the Israelites rebelled against me in the desert. They refused to obey my laws and teachings, and they treated the Sabbath like any other day. Then in my anger, I decided to destroy the Israelites in the desert once and for all.
If Abraham and his descendants were given this promise because they had obeyed a law, then faith would mean nothing, and the promise would be worthless.
Everything depends on having faith in God, so that God's promise is assured by his great kindness. This promise isn't only for Abraham's descendants who have the Law. It is for all who are Abraham's descendants because they have faith, just as he did. Abraham is the ancestor of us all.