Sunan Ibn Majah, Chapter: The Chapters of Purification and its Sunnah

Abu Sufyan said: "Abu Ayyub Al-Ansari, Jabir bin 'Abdullah, and Anas bin Malik told me that when this Verse: "In it (the mosque) are men who love to clean and to purify themselves. And Allah loves those who make themselves clean and pure."[9:108] was revealed, the Messenger of Allah (saw) said: 'O Ansar! Allah has praised you for your cleanliness. What is the nature of your cleanliness?' They said: 'We perform ablution for prayer and we take a bath to cleanse ourselves of impurity due to sexual activity, and we clean ourselves with water (after urinating). He said: 'This is what it is. So adhere to it.'" (Hasan)