Abraham believed God, that’s what justified Him before God (Genesis 15:6).
Psalm 32 says the same thing.
Abraham was uncircumcised when this happened, not circumcised.
So it’s by faith, as Abraham’s faith was strong against the physical evidence.
How this is about Jesus
Jesus is the object of Abraham’s faith, and ours. He is the one we believe to make us righteous before God.
Trust Jesus, and nothing else, to lift God’s condemnation against you for your sins.