Sunan Ibn Majah 1772
سنن ابن ماجه#1772Sahihحَدَّثَنَا إِسْحَاقُ بْنُ مُوسَى الْخَطْمِيُّ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنْ عُمَرَ، أَنَّهُ كَانَ عَلَيْهِ نَذْرُ لَيْلَةٍ فِي الْجَاهِلِيَّةِ يَعْتَكِفُهَا فَسَأَلَ النَّبِيَّ ـ صلى الله عليه وسلم ـ فَأَمَرَهُ أَنْ يَعْتَكِفَ .
It was narrated from ‘Umar that he had vowed during the days of Ignorance to spend one night in I’tikaf. He asked the Prophet (ﷺ) about it, so he commanded him to spend it in I’tikaf
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiSahih - Bukhari And Muslim
In-book reference: 7:135