Musannaf Ibn Abi Shayba 3:5270

Ghundar narrated to us, from Shu'bah, from Ya'la ibn 'Ata, who said: I heard Ibrahim ibn Yuhannis, from Abu al-Darda', who said: The likeness of the five prayers is like a man who has a river at his door, in which he bathes five times every day. So what does that leave of his filth?