In this whole passage (Romans 4:1-5, 13-17) it seems the apostle wants to show that there are two justifications, one by works and the other by faith. He says that justification by works has its glory but only in and of itself, not before God. Justification by faith, on the other hand, has glory before God, who sees our hearts and knows those who believe in secret and those who do not believe.

—Origen, Commentary on the Epistle to the Romans

Translation: Who’s your daddy?