NASAI-KUBRA 3335:
from ʿUmar —
ʿUmar said "O Messenger of Allah ﷺ! I vowed to perform Iʿtikaf for one night in Al-Masjid-al-Haram, during the Pre-Islamic Period of ignorance (before embracing Islam). "The Prophet ﷺ said, "Fulfill your vow." Ibn ʿUmar said to the lady, "Pray on her behalf." Ibn ʿAbbas said the same. (Using translation from Bukhārī 6697)
الكبرى للنسائي ٣٣٣٥:
عن عمر —
قُلْتُ يَا رَسُولَ اللهِ إِنِّي نَذَرْتُ أَنْ أَعْتَكِفَ لَيْلَةً فِي الْمَسْجِدِ الْحَرَامِ وَقَدْ جَاءَ اللهُ بِالْإِسْلَامِ فَقَالَ «أَوْفِ بِنَذْرِكَ»
hadithunlocked.com