How do we know that God's grace is sufficient for our failures?

God's grace shines brightly in the story of David in 1 Samuel 30, where David finds himself at rock bottom due to his own poor decisions. It's in this desperate state that he learns to rely on God's mercy, exemplified when he encourages himself in the Lord. David's cry for help signifies our need for God when we realize our own inadequacies and failures. Throughout the Bible, we see that God's grace is not dependent on our strength, but on His infinite mercy. As stated in John 1:29, Jesus, the Lamb of God, takes away the sin of the world, which includes our failures. Therefore, His grace sustains us, reminding us that salvation is of the Lord and not of ourselves.