Hadith 1817
Sayyiduna Abu Hurairah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) used to observe i'tikaf during the last ten days of Ramadan, and in the year in which he passed away, he observed i'tikaf for twenty days.
Hadith 1818
Umm al-Mu’minin Sayyidah Safiyyah bint Huyayy (may Allah be pleased with her) reported that she came to the Messenger of Allah (peace and blessings be upon him) in the mosque during the last ten days of Ramadan while he was observing i’tikaf. She spoke with the Messenger of Allah (peace and blessings be upon him) for a short while and then stood up (to return).