Musnad Ahmad 30:3402

Yazid narrated to us, Muhammad informed us, from Abu Salamah, from Abu Hurairah: A Bedouin entered the mosque while the Messenger of Allah, peace and blessings of Allah be upon him, was sitting. He said: "O Allah, forgive me and Muhammad, and do not forgive anyone along with us." The Messenger of Allah, peace and blessings of Allah be upon him, laughed and said: "You have restricted something vast." Then he turned away until, when he was in a corner of the mosque, he began to urinate. The Messenger of Allah, peace and blessings of Allah be upon him, stood up to him and said: "This house was only built for the remembrance of Allah and prayer, and it is not to be urinated in." Then he called for a bucket of water and poured it over it. The Bedouin said, after he had gained understanding: The Prophet, peace and blessings of Allah be upon him, stood up to me—may my father and mother be sacrificed for him—and he did not insult, nor did he rebuke, nor did he strike.