Musannaf Ibn Abi Shayba 3:5273

Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The likeness of the five prayers is like a flowing river at the door of one of you, in which he bathes five times every day." Al-Hasan said: "And what does that leave of filth?"