Any parent will understand the sentiment of what I mean when I say that, before I had children I never knew I could love someone so completely and so selflessly. This does not minimize love for others, but it does speak to the wonder of a new life being in the world for whom you are the cause. There is nothing you would not do for that child and, even as they grow up, you find yourself demonstrating the beauty of love in the many expressions of forgiveness. I know, at least for me and my siblings, my parents had to forgive on many occasions, and it seems like the well of mercy never dried up.
This is what we see in Psalm 51, but on a much higher and amazing level. David is not merely the son of Jesse. David is, as all of us are, a child of God. His life is owed to the power of creation which relates directly back to God. Sure, David was the king, but David was God's child and, as such, his posture is one of neediness rather than power or authority in this moment. He has offended his Father and now, comes before the Lord in the relationship as a son and asks for parental love. I think this is important as a model for all of us in understanding the love of God.
When we fail in our lives we have to feel the weight of guilt that is associated with sin, but we must never forget that, in Christ, our relationship to the Lord is now that of a child completely loved by the Father. The guilt of sin, however, is what often preoccupies the minds of so many such that we think, only, of the anger of the Lord. The reason guilt weighs so heavy at times is because we forget that God is our Father and that title is not simply an expression of His authority and control, but one of affection and love. The way new parents feel about their newborn, God feels infinitely and intensely about us. As parents forgive all the time, the Lord forgives and forgets. Why does he forgive like this? Because His love for us is the only way He chooses to relate to us as expressed in the life and work of the Lord Jesus Christ. This is why Paul could say, "but God shows his love for us in that while we were still sinners, Christ died for us" (Romans 5:8).
David comes to the Lord and pleads for forgiveness based on God's abundant mercy (Psalm 51:1). The word abundant is powerfully descriptive in its varied meaning of God's expression of love. The word signifies, first, the plurality of God's mercy. Some versions capture this thought by translating it this way, "according to the multitude of your tender mercies..." This plural meaning of the word shows that the mercies of God are not to be conceived of as simply the mercy of God (a singular, one time act) but the many mercies of God. In other words, God's mercy is so plentiful and sufficient that it can meet the number of sins that saints commit.
We can kind of comprehend this as we think about our love for our children because we forgive so much. We cannot conceive of anything that they could do that could prevent our love for them. Yet, there is one aspect of God's mercy that we cannot comprehend: He loves and shows mercy without anger towards His children. We get angry with our children when they defy us, but the Lord does not feel this way towards us when we defy Him. For those of us who are in Christ the Lord cannot be angry with us because all of His anger (wrath) for our sin was poured out, completely, on the cross. We can rightly say, therefore, that Christians cannot out-sin God's grace! We see this truth played out in the story of the prodigal son in Luke 15.
The prodigal defied tradition and his father by taking his inheritance before it was right to do so. He spent this money, all of it, on selfish and sensual passions only to wind up eating with pigs. When he decides to come back home (repent) his father welcomed him with open arms, gave him back his position and threw a party. That is not how I would have handled that, but the mercy of God is so plentiful that even my scandalous life does not stop His supernatural love. The Apostle Paul put it this way "...but where sin increased, grace abounded all the more, (Romans 5:20)
David asks for abundant mercy because he is a son and that is the beauty of gospel repentance. No matter what we have done our relationship with the Father does not change and we can plead for mercy on the basis that His mercy is plentiful. This does not minimize holiness, however. Repentance is not a one-sided matter. We cannot repent and keep sinning because such would prove a heart that is, at the least, insincere and worse, unconverted. Paul, knowing our inability to out-sin the grace of God still makes this point:
"What shall we say then? Are we to continue in sin that grace may abound? By no means! How
can we who died to sin still live in it” (Romans 6:1-2)?
Holiness is still the calling of the Christian. Yet, the Lord, knowing that we are dust has provided that our relationship with Him be sustained in and through the expression of His love for us in Christ alone.
God's mercies are plural, and this means that God has matching mercies for our sins. Whatever sin we commit the Lord has a mercy to match it. This means that there is no rebellion of life that God's mercy cannot match with love. David, knowing this as well as his varied depravity stated as transgression, iniquity and sin (Psalm 51:1-2) seeks the Lord for His plentiful or matching mercy. David needed a mercy for his transgression, one for his iniquity and another for his sin and God's love covered all of them with a love that matched each defilement. The same is true for us. What sin do you need mercy for? What sin do you need to see the defilement erasing mercy to clear away? God has a matching mercy for it.
When Christ died on the cross He was crushed for all of our particular sinfulness. The prophet Isaiah shows this best in his prophetic word about the sufferings of the coming Messiah:
4 Surely he has borne our griefs and carried our sorrows; yet we esteemed him stricken, smitten
by God, and afflicted. 5 But he was pierced for our transgressions; he was crushed for our
iniquities; upon him was the chastisement that brought us peace, and with his wounds we are
healed (Isaiah 53:4–5).
Every particularity of sin was crushed in the singularity of Christ's death: Our griefs he bore; Our sorrows he carried; Our transgressions pierced him; Our iniquities crushed him. This exchange brought forth life where our peace came by his being chastised for our sin and for us. Our healing came by him being wounded for our sin and for us
Whatever you have experienced and whatever sin has deceived you into obeying its seductive lure, God has a mercy for that in the blood of Christ. Here is the beauty of gospel repentance: it is a grace that has anticipated all of my rebellion and matched it, before I even committed the sin.