Sahih Muslim
The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fadail Al-Sahabah)
Book Number: 031 / Hadith Number: 6055
Ibn 'Abbas reported that Allah's Messenger (may peace be upon him) came to privy and I placed for him water for ablution, When he came out he said: Who placed it here? And in a version of Zuhair they (the Companions) said, and in the version of Abu Bakr (the words are): I said: It is Ibn 'Abbas (who has done that), whereupon he (the Holy Prophet) said: May Allah grant him deep understanding of religion.