I never said the law could save anyone. And I’m not sure if you are reading what I said. I was explaining how the law allowed for forgiveness of sin, and that it was a temporary covering until Christ came.
No I’m not Catholic. But God imputed righteousness on Abraham because of Abraham’s faith. God established a covenant with Abraham based on justification by faith. God established promises of salvation with Abraham that would extend to his seed, in Christ, that is those who believe in Jesus. God sealed that promise through circumcision. God established, through Abraham, the line His Son, Jesus, would come through to save man, and that line was through Abraham and his seed. When Jesus was born He was born into Abraham seed to assure the promise made to Abraham that he would be the father of many nations. Jesus being our sacrifice, our lord and savior, grafts the believers into the seed of Abraham as children of God where they inherit the kingdom as heirs of God and co- heirs with Christ.
God Has already deemed Abraham righteous and sealed his righteousness, but he could not receive eternal life until Christ came. The reason Abraham had to wait for Christ to be resurrected is because only Christ can give eternal life.
This pdf gives some background on Abraham:
