Arabic (Original)
حَدَّثَنَا مُحَمَّدٌ حَدَّثَنَا شُعْبَةُ عَنْ عُبَيْدِ اللَّهِ بْنِ عُمَرَ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ أَنَّ عُمَرَ كَانَ قَدْ جَعَلَ عَلَيْهِ يَوْمًا يَعْتَكِفُهُ فِي الْجَاهِلِيَّةِ فَسَأَلَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنْ ذَلِكَ فَأَمَرَهُ أَنْ يَعْتَكِفَ.
English Translation
Muhammad told us, Shu'bah told us, from Ubaydullah ibn Umar, from Nafi', from Ibn Umar, that Umar had vowed during the pre-Islamic era to perform a day of i'tikaf. He asked the Messenger of Allah, peace and blessings be upon him, about that, and he ordered him to perform the i'tikaf.