1. Abraham's faith (1-5)
Abraham was the forefather of Israel. Was he justified before God by his faith or by his works? Paul quotes Genesis 15:6, "Abraham believed God, and it was credited to him as righteousness." Abraham believed God's unrealistic promise that he would have a child and his offspring would be as numerous as the stars. God was pleased with Abraham's faith. Without faith, we can't please God (Heb 11:6). Abraham was not justified by his works but by his faith and trust in God's word.
2. David's faith (6-8)
David also testifies to this saving faith in Psalm 32 (take one minute to read it). David found the blessing of forgiveness of sin not by doing good works, but by acknowledging and confessing his sin (Ps 32:5). He too was justified and forgiven when he simply came to God in faith and trust.