The Prophet ﷺ said that this verse was revealed concerning the people of Quba, "In it are men who love to purify themselves, and Allah loves those who purify themselves" [Tawbah 9:108]. He said, "They used to clean themselves with water after relieving themselves, so this verse was revealed about them."He said, this hadith is rare from this chain of narration.
حدثنا محمد بن العلاء أبو كريب حدثنا معاوية بن هشام حدثنا يونس بن الحارث عن إبراهيم بن أبي ميمونة عن أبي صالح
عن النبي ﷺ قال نزلت هذه الآية في أهل قباء {فيه رجال يحبون أن يتطهروا والله يحب المطهرين} قال كانوا يستنجون بالماء فنزلت هذه الآية فيهم قال هذا حديث غريب من هذا الوجه
[Hasan] Abu Dawud narrated it in the Book of Purification, Chapter on Cleaning Oneself with Water, no. 44, from Abu Kurayb with the same wording. It has a corroborating narration in Ibn Majah, no. 355, with a hasan chain, and Hakim graded it sahih, 1/155, and Dhahabi agreed with him.There are also narrations on this subject from Abu Ayub and Anas bin Malik [Ibn Majah, no. 355] and Muhammad bin Abdullah bin Salam [Ahmad, 6/6].