Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
nasai-kubra:4744 – Muḥammad b. ʿAbdullāh b. Yazīd > Sufyān > Ayyūb > Nāfiʿ > Ibn ʿUmar

"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." (Using translation from Nasāʾī 3821)   

الكبرى للنسائي:٤٧٤٤ – أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللهِ بْنِ يَزِيدَ قَالَ حَدَّثَنَا سُفْيَانُ قَالَ حَدَّثَنَا أَيُّوبُ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ قَالَ

كَانَ عَلَى عُمَرَ بْنِ الْخَطَّابِ نَذْرٌ فِي اعْتِكَافِ لَيْلَةٍ فِي الْمَسْجِدِ الْحَرَامِ فَسَأَلَ رَسُولَ اللهِ ﷺ «فَأَمَرَهُ أَنْ يَعْتَكِفَ»  

See similar narrations below:

Collected by Nasāʾī, Nasāʾī's Kubrá
nasai:3821 – Muḥammad b. ʿAbdullāh b. Yazīd > Sufyān > Ayyūb > Nāfiʿ > Ibn ʿUmar

"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."  

النسائي:٣٨٢١ – أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ يَزِيدَ قَالَ حَدَّثَنَا سُفْيَانُ عَنْ أَيُّوبَ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ قَالَ

كَانَ عَلَى عُمَرَ نَذْرٌ فِي اعْتِكَافِ لَيْلَةٍ فِي الْمَسْجِدِ الْحَرَامِ فَسَأَلَ رَسُولَ اللَّهِ ﷺ عَنْ ذَلِكَ فَأَمَرَهُ أَنْ يَعْتَكِفَ  

nasai-kubra:3339 – Muḥammad b. ʿAbdullāh b. Yazīd > Sufyān > Ayyūb > Nāfiʿ > Ibn ʿUmar

"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." (Using translation from Nasāʾī 3821)  

الكبرى للنسائي:٣٣٣٩ – أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللهِ بْنِ يَزِيدَ قَالَ حَدَّثَنَا سُفْيَانُ قَالَ حَدَّثَنَا أَيُّوبُ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ قَالَ

كَانَ عُمَرُ نَذَرَ فِي الْجَاهِلِيَّةِ اعْتِكَافِ لَيْلَةٍ فِي الْمَسْجِدِ الْحَرَامِ «فَسَأَلَ رَسُولَ اللهِ ﷺ عَنْ ذَلِكَ فَأَمَرَهُ أَنْ يَعْتَكِفَ»