Musnad Ahmad 32:363

Ibn Abi ‘Adi narrated to us, from Ibn ‘Awn, from Anas, from ‘Abd al-Hamid ibn al-Mundhir ibn Jarud, from Anas ibn Malik, who said: Some of my paternal uncles prepared food, and he said to the Prophet, peace and blessings of Allah be upon him: "I would like for you to eat in my house and pray in it." He said: "So he came, and there was a stallion from those stallions in the house." He said: "He ordered a corner of it, so it was swept and sprinkled [with water], and he prayed, and we prayed."