Not one person is righteous. To be righteous means to be free from all sin. The only righteous person is Jesus Christ himself. No person is capable of working hard enough to be righteous. In this passage, Paul is quoting David from the Old Testament (Psalm 14). It is essential we understand that no man is righteous, all have sinned, and we all require the salvation of Jesus Christ to attain perfection in the eyes of God the Father.