Sunan Abi Dawud 646
سنن أبي داود#646HasanNarrated AbuRafi': Sa'id ibn AbuSa'id al-Maqburi reported on the authority of his father that he saw AbuRafi' the freed slave of the Prophet (ﷺ), passing by Hasan ibn Ali (Allah be pleased with them) when he was standing offering his prayer. He had tied the back knot of his hair. AbuRafi' untied it. Hasan turned to him with anger, AbuRafi' said to him: Concentrate on your prayer and do not be angry: I heard the Messenger of Allah (ﷺ) say: This is the seat of the devil, referring to the back knot of the hair
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan
Muhammad Muhyi Al-Din Abdul HamidHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 2:256