Romans 4:2, 13-15

If his good deeds had made him acceptable to God, he would have had something to boast about. But that was not God’s way.

Clearly, God’s promise to give the whole earth to Abraham and his descendants was based not on his obedience to God’s law, but on a right relationship with God that comes by faith. If God’s promise is only for those who obey the law, then faith is not necessary and the promise is pointless. For the law always brings punishment on those who try to obey it. (The only way to avoid breaking the law is to have no law to break!)