Sunan Abi Dawud 2466
سنن أبي داود#2466SahihAbu Hurairah said:The Prophet (ﷺ) used to observe I'tikaf during ten days of Ramadan every year. But when the year in which he died, he observed I'tikaf for twenty days
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan Sahih
Muhammad Muhyi Al-Din Abdul HamidHasan Sahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Bukhari (2044)
In-book reference: 14:154