'Aishah (May Allah be pleased with her) reported:
The Prophet (ﷺ) used to engage himself in I'tikaf (seclusion for prayers) in the mosque during the last ten nights of Ramadan till he passed away; thereafter, his wives followed this practice after him.[Al- Bukhari and Muslim]. (IT)
App reference (IT): Book 10, Hadith 2 (IT)
Arabic/English book reference (IT): Book 10, Hadith 1269 (IT)