Reference
ID 5700
Collector Muslim ibn al-Hajjaj
Book Sahih Muslim
Chapter The Book of Oaths
Reference (English Book) Book 15, Hadith 4072
Reference (Arabic Book) Book 28, Hadith 4382
Hadith Type Atar
Matn (English)

Ibn 'Umar reported that Umar (b. Khattab) said: Messenger of Allah, I had taken a vow during the days of Ignorance (Jahiliyya) that I would observe I'tikaf for a night in the Sacred Mosque. He (the Holy Prophet) said: Fulfil your vow.

Matn (Arabic)

حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي بَكْرٍ الْمُقَدَّمِيُّ، وَمُحَمَّدُ بْنُ الْمُثَنَّى، وَزُهَيْرُ بْنُ حَرْبٍ، - وَاللَّفْظُ لِزُهَيْرٍ - قَالُوا حَدَّثَنَا يَحْيَى، - وَهُوَ ابْنُ سَعِيدٍ الْقَطَّانُ - عَنْ عُبَيْدِ اللَّهِ، قَالَ أَخْبَرَنِي نَافِعٌ، عَنِ ابْنِ عُمَرَ، أَنَّ عُمَرَ، قَالَ يَا رَسُولَ اللَّهِ إِنِّي نَذَرْتُ فِي الْجَاهِلِيَّةِ أَنْ أَعْتَكِفَ لَيْلَةً فِي الْمَسْجِدِ الْحَرَامِ ‏.‏ قَالَ ‏ "‏ فَأَوْفِ بِنَذْرِكَ ‏"‏ ‏.‏