Why did Paul call his gospel the Gospel of the Grace of God?
Because God's grace much more abounds where sin abounded. God loves even the ungodly and can reach below the vilest sinner, lift him up, and make him a saint. That is why Paul refers to his Gospel as the Gospel of the Grace of God.
Les explains that where sin abounded, grace did much more abound. He notes that everyone knows someone who seems ungodly, hateful toward God, and living like a reprobate, whom most people do not even like to associate with, yet God still loves them. God is able to reach below the vilest sinner, lift him up, and make him a saint. Because grace so far exceeds sin, Paul calls his Gospel the Gospel of the Grace of God. In the closing minutes, Les moves to Romans 10:9-13, stressing that God expects verbalization—confessing with the mouth and telling God you recognize from Scripture that you are a sinner.