Musnad Ahmad 33:736

Ammar ibn Muhammad narrated to us, from al-A’mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The likeness of these five prayers is like a flowing river at the door of one of you, in which he bathes five times every day. So, what does that leave of filth?"