Shmuel Bais 11:2-5

And it came to pass at haerev, that Dovid arose from off his mishkav (bed), and walked upon the gag of the Bais HaMelech; and from the gag (roof) he saw an isha bathing; and the isha was very good to look upon. And Dovid sent and inquired after the isha. And one said, Is not this Bat-Sheva Bat Eli'am, eshet Uriyah the Chitti? And Dovid sent malachim, and he got her; and she came in unto him, and he lay with her; for she had been purifying herself from her tumah (uncleanness); and she returned unto her bais. And the isha conceived, and sent and told Dovid, and said, Harah anochi (I am with child, I am pregnant).