Who can tell - David, and indeed all others under the Mosaic dispensation, were so satisfied that all God's threatenings and promises were conditional, that even in the most positive assertions relative to judgments, etc., they sought for a change of purpose. And notwithstanding the positive declaration of Nathan, relative to the death of the child, David sought for its life, not knowing but that might depend on some unexpressed condition, such as earnest prayer, fasting, humiliation, etc., and in these he continued while there was hope. When the child died, he ceased to grieve, as he now saw that this must be fruitless. This appears to be the sole reason of David's importunity.

And he said, while the child was yet alive,.... And so there was hope it might be continued:

I fasted and wept; or sought the Lord by prayer, and fasting, and weeping, that the threatening might not take place, that the child's life might be spared:

for I said; within himself, thus he reasoned in his own mind:

who can tell whether God will be gracious to me, that the child may live? and in hope of this he kept praying, fasting, and weeping; he could not tell but God might repent of the evil he had threatened, as in some cases he has done; see Joel 2:13. Abarbinel thinks that David fasted and wept to hide this matter from his wife, and his servants, and did not let them know that this was in his punishment, that the child should die.

And he said, While the child was yet alive, I fasted and wept: for I said, Who can tell whether GOD will be gracious to me, that the child may live?

12:15-25 David now penned the 51st Psalm, in which, though he had been assured that his sin was pardoned, he prays earnestly for pardon, and greatly laments his sin. He was willing to bear the shame of it, to have it ever before him, to be continually upbraided with it. God gives us leave to be earnest with him in prayer for particular blessings, from trust in his power and general mercy, though we have no particular promise to build upon. David patiently submitted to the will of God in the death of one child, and God made up the loss to his advantage, in the birth of another. The way to have creature comforts continued or restored, or the loss made up some other way, is cheerfully to resign them to God. God, by his grace, particularly owned and favoured that son, and ordered him to be called Jedidiah, Beloved of the Lord. Our prayers for our children are graciously and as fully answered when some of them die in their infancy, for they are well taken care of, and when others live, beloved of the Lord.