By giving his laws to the Jews, God has not canceled what he promised to Abraham much earlier concerning his descendant, Christ. Just like God gave his blessings to Abraham just because he promised to do so, he freely gives his blessings to us.

Galatians 3:15-18

15 My fellow believers, I will now illustrate by referring to human relationships. After an agreement is confirmed by two people {two people have signed an agreement}, no one can reject it or add to it. 16 God declared to Abraham and his descendant that he was promising to give blessings to Abraham. The words that God spoke were not “and your descendants.” He was not referring to many persons. Instead, he was referring to one person, who is Christ, because the words that God spoke were, “and your descendant.” 17 This is what I am saying: Since God gave the laws to the Jews 430 years after he declared to Abraham what he was promising to do for Abraham, those laws do not cancel that agreement with Abraham that God himself had previously agreed about [PRS]. 18 Remember that if it is because we obey God’s laws that he gives to us what he has promised to give to us, then it is not just because he has promised that he would give those things to us. God freely gave to Abraham what he had promised to give to him, just because God had promised that he would give it to him. Similarly, it is not because we obey God’s laws that God gives to us what he has promised to give to us.