Sunan Ibn Majah 1770
سنن ابن ماجه#1770SahihIt was narrated from Ubayy bin Ka’b that:The Prophet (ﷺ) used to spend the last ten days of Ramadan in I’tikaf. One year he was traveling, so the following year he spent twenty days in I’tikaf
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 7:133