question #2 Sahih al-Bukhari 2043, Book 33, Hadith 18 : How does Islam view the practice of I`tikaf and its importance in worship?

that `Umar had vowed in the Pre-Islamic period to perform I`tikaf in Al-Masjid-al-Haram. (A subnarrator
thinks that `Umar vowed to perform I`tikaf for one night.) Allah’s Messenger (ﷺ) said to `Umar,
“Fulfill your vow.”