2 Samuel 11:1-2

Then it happened in the spring, at the time when the kings go out to battle, that David sent Joab and his servants with him, and all [the fighting men of] Israel, and they destroyed the Ammonites and besieged Rabbah. But David remained in Jerusalem. One evening David got up from his couch and was walking on the [flat] roof of the king’s palace, and from there he saw a woman bathing; and she was very beautiful in appearance.