Charles Ellicott Commentary 2 Samuel 11:27

"And when the mourning was past, David sent and took her home to his house, and she became his wife, and bare him a son. But the thing that David had done displeased Jehovah." — 2 Samuel 11:27 (ASV)

Bare him a son. —Several months must have passed since the beginning of David’s course of sin, and yet his conscience had not made him aware of what he had done, nor had the prophet Nathan been sent to him. It should be remembered that during all this time David was not only the civil ruler of his people, but also the head of the theocracy, the great upholder of the worship and the service of God, and his psalms were used as the vehicle of the people’s devotion.

If it is asked why he should have been left so long without being brought to a conviction of his sin, one obvious reason is that this sin might be openly fixed upon him beyond all possibility of denial by the birth of the child. But besides this, however hardened David may appear to have been in passing from one crime to another in the effort to conceal his guilt, it is scarcely possible that his conscience was not meanwhile at work and oppressing him with that sense of unconfessed and unforgiven sin which ultimately prepared him for Nathan's visit.