Romans 4:13 It was not through law that Abraham and his offspring received the promise that he would be heir of the world, but through the righteousness that comes by faith.
Abraham is a man of faith. When God told him he will be the father of all nations - he has no son. But he believed and received the promise of God. Abraham received the promise before the law was given.
Galatians 3:14 He redeemed us in order that the blessing given to Abraham might come to the Gentiles through Christ Jesus, so that by faith we might receive the promise of the Spirit.
Genesis 28:14 Your descendants will be like the dust of the earth, and you will spread out to the west and to the east, to the north and to the south. All peoples on earth will be blessed through you and your offspring.
All the things we have in faith has no value if we are justified by law. The promise is worthless if the Jews seek to be justified by morality - they can't depend on any promise of God.
1 John 3:4 Everyone who sins breaks the law; in fact, sin is lawlessness.
Justification is by faith.
Romans 3:26 he did it to demonstrate his justice at the present time, so as to be just and the one who justifies those who have faith in Jesus.
God doesn't save people because we are goo but He save people cause He is good.
Ephesians 2:8-9 For it is by grace you have been saved, through faith--and this not from yourselves, it is the gift of God--
not by works, so that no one can boast.
Galatians 2:21 I do not set aside the grace of God, for if righteousness could be gained through the law, Christ died for nothing!"
Hebrews 11:11 By faith Abraham, even though he was past age--and Sarah herself was barren--was enabled to become a father because he considered him faithful who had made the promise.