It was narrated from Ibn 'Umar that 'Umar had vowed -during the Jahiliyyah- to spend a day in 'Itikaf. He asked the Messenger of Allah about that, and he commanded him to perform the 'Itikaf.
Sunan an-Nasa'i Book 35, Hadith 62
← Previous Hadith "Umar had made a vow to spend a night in 'Itikaf in Al-Masjid Al-Haram. He asked the Messenger of Allah about that, and he ordered him to perform the 'Itikaf."

Sunan an-Nasa'i Book 35, Hadith 61 Next Hadith → "O Messenger of Allah! I want to give all my wealth in charity for Allah and His Messenger." The Messenger of Allah said to him: "Keep some of your wealth for yourself; that is better for you."

Sunan an-Nasa'i Book 35, Hadith 63