Jami` at-Tirmidhi 803

جامع الترمذي#803Sahih

Anas bin Malik narrated:"The Prophet would perform I'tikaf during the last ten (nights) of Ramadan. One year he did not perform I'tikaf, so he performed I'tikaf for twenty (nights) in the following year

Scholarly Authentication

We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:

Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih

In-book reference: 8:122