Amy once asked the Eleventh Doctor what do Time Lords pray to? The Doctor dodged the question, but we got an answer way back in The Satan Pit. The Tenth Doctor is facing down the devil itself, after having been mocked, manipulated, and threatened by it for the last episode. Its finally trapped him, manipulating the situation so that the Doctor will have to sacrifice Rose in order to kill him. At that point, the Doctor says that hes seen a lot of things. Ive seen bad gods and demigods and would-be gods. And you know what, out of that whole pantheon, if I believe in one thing, just one, I believe in her. An alien being of unimaginable age, whos seen more of the universe than any living creature, who technically qualifies as a god himself. And what does he believe in? A girl. A young human woman. He believes that she will always be herself, that she will never just be a victim in the great games of the universe. He believes that she will find a way to survive, that she will still be there. The Doctor prays to people.