Psalm 51: 1-6To the choirmaster. A Psalm of David, when Nathan the prophet went to him, after he had gone in to Bathsheba.
1 Have mercy on me,[a] O God,
according to your steadfast love;
according to your abundant mercy
blot out my transgressions.
2 Wash me thoroughly from my iniquity,
and cleanse me from my sin!
3 For I know my transgressions,
and my sin is ever before me.
4 Against you, you only, have I sinned
and done what is evil in your sight,
so that you may be justified in your words
and blameless in your judgment.
5 Behold, I was brought forth in iniquity,
and in sin did my mother conceive me.
6 Behold, you delight in truth in the inward being,
and you teach me wisdom in the secret heart.
a. Psalm 51:1 Or Be gracious to me
The repentance which, in this psalm, he expresses, he was brought to by the ministry of Nathan, who was sent of God to convince him of his sin, after he had continued above nine months (for aught that appears) without any particular expressions of remorse and sorrow for it. But though God may suffer his people to fall into sin, and to lie a great while in it, yet he will, by some means or other, recover them to repentance, bring them to himself and to the right mind again.
Multiply to wash me; the stain is deep, for I have lain long soaking in the quilt, so that it will not easily be got out.
Sin defiles us, renders us odious in the sight of the holy God, and uneasy to ourselves.
It will be of good use for us to have our sins ever before us, that by the remembrance of our past sins we may be kept humble, may be armed against temptation, quickened to duty, and made patient under the cross.
It is good to be particular in the confession of sin, that we may be the more express in praying for pardon, and so may have the more comfort in it.
This should greatly humble us for all our sins, that they have been committed under the eye of God, which argues either a disbelief of his omniscience or a contempt of his justice.
Had I only considered this before, I find I should not have made so bold with the temptation, not have ventured among the sparks with such tinder in my heart; and so the sin might have been prevented.
Truth and wisdom will go very far towards making a man a good man. A clear head and a sound heart (prudence and sincerity) bespeak the man of God perfect.
Matthew Henry, Commentary of the Bible, Psalm LI, vs. 1-6, highlights (these were taken from my reading and underlining of key concepts on November 14, 1987, still true today)