Musnad Ahmad 32:534

Abu Sa'id narrated to us, 'Abd al-'Aziz—meaning Ibn 'Abd Allah ibn Abi Salamah—narrated to us, Ishaq ibn 'Abd Allah ibn Abi Talhah narrated to us, from Anas ibn Malik, who said: "The Messenger of Allah (ﷺ) prayed with us in the house of Umm Sulaym, upon an old mat that had changed due to age." He said: "And I sprinkled it with some water, so he prostrated upon it."