Purge me with hyssop, and I shall be clean; wash me and I will be whiter than snow. Make me to hear joy and gladness, that the bones You have broken may rejoice. Hide Your face from my sins and blot out all my iniquities. Psalm 51:7-9
David was crying out for forgiveness as he more than likely remembered the blood that was used to purify the children of Israel in Egypt the night the death angel came to kill the firstborn! Hyssop was used to apply the blood to the doorposts to protect them from God's judgement.
Man's forgiveness doesn't go as far as God's, especially when one has committed murder and adultery! To commute two death sentences today would be very unlikely but with God all things are possible! God is not like man, He is holy and His divine nature allows Him to go to extreme limits to deliver and forgive all who confess and repent!
Remember when Nathan told David the story about the man who took his servant's lamb and served it up for his guest? David enraged said, "That man shall die!" But he was that man! Forgiveness is the centerpiece of Christianity, to forgive and forget man's sins because that is the divine nature and character of a holy God, and we should also forgive!
"For if you forgive men their trespasses, your heavenly Father will also forgive you. "But if you do not forgive men their trespasses, neither will your Father forgive your trespasses." Matthew 6:14,15
Your servant in Christ, Timothy Laughlin
Minister of the Gospel of Jesus Christ