Sunan Abi Dawud 44
سنن أبي داود#44SahihNarrated AbuHurayrah: The Prophet (ﷺ) said: The following verse was revealed in connection with the people of Quba': "In it are men who love to be purified" (ix.108). He (AbuHurayrah) said: They used to cleanse themselves with water after easing. So the verse was revealed in connection with them
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautHasan Lighairihi
Zubair Ali ZaiHasan
In-book reference: 1:44