2 Samuel 12:16

David … went in. He went, not into the sanctuary, which he did not enter until after the child's death, but into some private room in his own house. There he remained, passing his nights stretched on the ground, and fasting until the seventh day. His fasting does not imply that he took no food during this long interval, but that he abstained from the royal table, and ate so much only as was necessary to maintain life. Now, what was the meaning of this privacy and abstinence? Evidently it was David's acknowledgment, before all his subjects, of his iniquity, and of his sorrow for it. The sickness of the child followed immediately upon Nathan's visit, and we may feel sure that news of his rebuke, and of all that passed between him and the king, ran quickly throughout Jerusalem. And David at once takes the position of a condemned criminal, and humbles himself with that thoroughness which forms so noble a part of his character. Grieved as he was at the child's sickness, and at the mother's sorrow, yet his grief was mainly for his sin; and he was willing that all should know how intense was his shame and self-reproach. And even when the most honourable of the rulers of his household ( Genesis 24:2 ), or, as Ewald thinks, his uncles and elder brethren, came to comfort him, he persists in maintaining an attitude of heart stricken penitence.