"You are forgiving and good, O Lord, abounding in love to all who call to you.” (v.5)
Forgiveness is at the heart of our relationship with God. Ever since the Fall, humans have been sinning and repenting, and God has been redeeming, forgiving, and restoring. Such mercy and grace best show His character (vv. 13, 15). In response to these truths, David proclaimed God’s greatness and His worthiness to be worshiped, as well as our responsibility to obey and glorify Him.
Satan, on the other hand, wants us to think that we’ve committed something unforgivable each time we sin, “Surely God could never forgive me. After all, what I did was so horrible … ” Such thoughts are his speciality--he wants you to believe that God’s love is less than what it is. Don’t believe the lie, David didn’t - And he was right up there in terms of committing what we would see as, unforgivable sin.
Therefore, pour out your heart to Him, "For it is with your heart that you believe and are justified, and it is with your mouth that you profess your faith and are saved.” (Romans 10:10)
The Truth: "Whoever conceals their sins does not prosper, but the one who confesses and renounces them finds mercy.” (Proverbs 28:13)