Musannaf Ibn Abi Shayba 27:224

Ghundar narrated to us, from Shu'bah, from Sa'd ibn Ibrahim, who said: I heard Humayd ibn 'Abd al-Rahman narrating from Abu Hurayrah, from the Prophet (may Allah bless him and grant him peace), that he said: Allah (Mighty and Majestic is He) said: "It is not befitting for a servant of Mine to say, 'I am better than Yunus ibn Matta.'"