This psalm purports to be a psalm of David, and the contents of it accord with this supposition, and with the statement in the title in regard to the occasion on which it was composed. There would be no difficulty on the subject, and no ground for hesitation, in regard to the author and the occasion on which it was composed, if it were not for the prayer in Psalms 51:18, “Do good in thy good pleasure unto Zion; build thou the walls of Jerusalem,” which, it has been maintained by DeWette, Rosenmuller, Venema, and others, must have been written in the time of the Babylonian cxile. Except this, it is admitted on all hands that the psalm in its composition accords entirely with the statement in the title, that it was composed by David. It has, in fact, been generally admitted that the psalm “was” composed by David, though it is the opinion of Rosenmuller, Venema, and Doederlein, that the last two verses were added by a later hand.
According to the title, the psalm was composed on occasion of the great fault and crime in the life of David, and as an expression of his penitence in view of his sin. On the phrase “To the chief Musician,” see the notes at the title to Psalms 4:1-8. We are not to suppose that this title was prefixed to the psalm by David himself, but the use to be made of it by committing it to the “chief Musician,” or to the overseer of the music in the public worship of God shows that the psalm was considered as designed to be used in public, and was not a mere expression of the private feelings of the author. It was, doubtless, commonly understood (and was probably so intended by David himself) that it was to be used as a “public” expression of his penitence in view of his crane; and both the fact of its composition, and the manner in which it was to be used, were to be interpreted as indicating his willingness that the widest publicity should be given to his confession, and that the memory of the crime and of his penitence should be perpetuated in all ages of the world. The phrase in the title, “A “Psalm” of David,” denotes that it was to be used for public worship, or as connected with praise. It was designed not merely to express his private feelings, but was intended to be employed in the solemn services of public devotion. See introduction to Psalms 3:1-8.
The phrase “when Nathan the prophet came unto him,” refers to the fact recorded in 2 Samuel 12:1-13. It means that the psalm was the “result” of the visit of Nathan to him; or that it records the feelings of the author, when the sense of his sin had been brought to his mind by the faithful message of the prophet. We may suppose that the record of his feelings was made without delay, for the psalm bears all the marks of having been composed under the deepest feeling, and not of being the result of calm reflection. On the phrase “after he had gone in to Bath-sheba,” see the sad record in 2 Samuel 11:1-5.
DeWette, however, maintains that psalm could not have been composed David, but that it must have been in the time of the Babylonian exile. The only argument which he adduces in favor of this opinion is the prayer in Psalms 51:18, “Build thou the walls of Jerusalem,” which, he says, could not have been a prayer offered by David, as there was in his time nothing which would make this prayer proper. Jerusalem was not then in ruins. It had been strongly fortified by David himself, and required no particular interposition of God as if to “restore” walls that had been thrown down; whereas, in the time of the exile, such a prayer would have been eminently proper, and would be a natural petition for one who loved his country, and who, as an expression of his own penitence, was desirous of doing all he could for the cause of religion. The difficulty will be more appropriately met in the notes at those verses.
It may be observed here, however, that possibly the expression “Build thou the walls of Jerusalem,” “may” be used in a figurative or spiritual sense, expressive of a desire that God would bless his people; that he would interpose in their behalf; that he would be their protector and friend; that he would do for them what would be well expressed by building strong and secure wails around a city. But it may be asked, also, Is it absolutely certain that when the psalm was composed the work of enclosing the city of Jerusalem with walls had been completed? May it not have been, in fact, that at that very time David was engaged in “carrying out” his design of rendering the city impregnable by walls and towers, and that in the midst of his intense sorrow for his own sin, though so heinous and aggravated, his heart may have trurned to that which was so dear to him as an object to be accomplished, and that even then, in connection with his bitter repentance for his sin, he may have prayed that God would favor that great design?
It is no evidence that our sorrow for sin is not deep and genuine, that, even in our expressions of penitence, our heart turns to Zion - to the Church - to the great work which the Church is accomplishing - and that, though our prayers “began” with a reference to our own sin, they should “close” with a petition that God would bless his people, and fulfill the great purposes so near to the heart of piety in reference to the progress of true religion in the world. Indeed, from the very narrative in 2 Sam. 6–12. it would seem probable that the work of fortifying the city of Jerusalem, contemplated by David, was not yet completed, when he committed the crime for which this psalm is the expression of penitence. It was a work of years to do this: and it is not improbable that the guilty transaction to which this psalm refers occurred in the very midst of his design for the defense and protection of the capital of his kingdom.
The psalm consists of two parts:
I. In the first Psalms 51:1-12, the psalmist confesses his guilt, and prays for pardon. He begins with an earnest plea for mercy Psalms 51:1-2; he humbly acknowledges his offence, without any attempt to vindicate himself, or to apologise for it Psalms 51:3-6; he pleads with God to cleanse him, to pardon him, to create in him a new heart, and not to cast him off or to take his Holy Spirit from him Psalms 51:7-12.
II. In the second part Psalms 51:13-19 he shows how he would manifest his sense of the divine mercy if he was forgiven: expressing the purpose to lead a new life; to devote himself to the duties of religion; to do all in his power to repair the evils of his conduct, and especially to induce others to avoid the way of sin, warning them by his example. He says that he would teach transgressors the true ways of God, and that sinners would be converted to Him, Psalms 51:13; that he would sing aloud the praise of God, Psalms 51:14-15; that he would offer to God the sacrifice of a broken heart and a contrite spirit, Psalms 51:16-17; and he then pleads Psalms 51:18-19, that God would interpose and bless Zion, that the great work might be completed in which he had been engaged in defending the city, and in preparing a place which would be secure, where God might be worshipped, and where sacrifices and offerings might perpetually ascend on his altar.