2 Samuel 12:1

Unto him, after the birth of the child. A whole year had nearly elapsed, and David continued blind and impenitent. The spirit of prophecy had left him; and, though he was clear-sighted, and equitable enough to punish the faults of others, he could not discern his own picture, till Nathan had removed the veil. The prophet acted with the utmost prudence, and did not condemn the king till he had pronounced sentence on himself. It is commonly supposed that the interview was private. St. Chrysostom believes that the chief lords of the court were present; which would enhance the discretion of Nathan, as well as David's humility. (Calmet)