It is narrated from Sayyiduna Ubayy ibn Ka'b (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) used to observe i'tikaf during the last ten days of Ramadan, but one year he had to undertake a journey, due to which he could not observe i'tikaf. Then, the following year, he observed i'tikaf for twenty days.
Hadith Referenceالفتح الربانی / كتاب الصيام / 3997
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«اسناده صحيح علي شرط مسلم۔ اخرجه ابوداود: 2463، وابن ماجه: 1770، (انظر مسند أحمد ترقيم الرسالة: 21277 ترقیم بيت الأفكار الدولية: 21600»