To the chief Musician, A Psalm of David, when Nathan the prophet came unto him, after he had gone in to Bathsheba. The occasion of this psalm was the sin of David with Bathsheba, signified by "going in to her"; an euphemism for "lying with her"; which sin was a very aggravated one, she being another man's wife, and the wife of a servant and soldier of his, who was at the same time exposing his life for his king and country's good; and David besides had many wives, and was also king of Israel, and should have set a better example to his subjects; and it was followed with other sins, as the murder of Uriah, and the death of several others; with scandal to religion, and with security and impenitence in him for a long time, until Nathan the prophet was sent to him of God, to awaken him to a sense of his sin; which he immediately acknowledged, and showed true repentance for it: upon which, either while Nathan was present, or after he was gone, he penned this psalm; that it might remain on record, as a testification of his repentance, and for the instruction of such as should fall into sin, how to behave, where to apply, and for their comfort.
The history of all this may be seen in the eleventh and twelfth chapters of the second book of Samuel.Ver. 1. Have mercy upon me, O God,.... David, under a sense of sin, does not run away from God, but applies unto him, and casts himself at his feet, and upon his mercy; which shows the view he had of his miserable condition, and that he saw there was mercy in God, which gave him hope; and upon his bended knees, and in the exercise of faith, he asks for it;according to thy lovingkindness; not according to his merits, nor according to the general mercy of God, which carnal men rely upon; but according to his everlasting and unchangeable love in Christ; from which as the source, and through whom as the medium, special mercy comes to the children of men.
The acts of special mercy are according to the sovereign will of God: he is not moved to mercy neither by the merits nor misery of men, but by his free grace and favour; it is love that sets mercy to work: this is a most glaring gleam of Gospel light, which none of the inspired writers besides, except the Apostle Paul, saw, Eph 2:4;according unto the multitude of thy tender mercies blot out my transgressions; for his sin was complicated, attended with many others; and, besides, upon a view of this, he was led to observe all his other sins; and particularly the corruption of his nature, his original sin, which he mentions, Ps 51:5.
These he desires might be "blotted out"; out of the book of account, out of God's debt book; that they might not stand against him, being debts he was not able to pay or make satisfaction for; and out of the table of his own heart and conscience, where they were ever before him, and seemed to be engraven; that they might be caused to pass from him, and he might have no more conscience of them; or that they might be blotted out, as a cloud by the clear shining of the sun of righteousness, with the healing of pardoning grace in his wings; or that they might be wiped away, as any faith is wiped from any person or thing: and all this "according to the multitude of [his] tender mercies".
The mercy of God is plenteous and abundant; he is rich in it, and various are the instances of it; and it is exceeding tender, like that of a father to his children, or like that of a mother to the son of her womb; and from this abundant and tender mercy springs the forgiveness of sin, Lu 1:77.