Musannaf Ibn Abi Shayba 33:962

Muhammad ibn Bishr narrated to us, he said: Sufyan narrated to us, he said: Abu Hammam narrated to us, from al-Hasan, who said: May Allah have mercy on a servant who pauses at his intention. For there is no servant who acts until he intends; so if it is good, he carries it out, and if it is evil, he refrains from it.