Hadith 191

Bulugh al-Maram

Book 2: The Book of Prayer
وَلِأَحْمَدَ وَاَلدَّارَقُطْنِيِّ نَحْوُهُ مِنْ وَجْهٍ آخَرَ , وَزَادَ : { فَأَمَّا فِي اَلصُّبْحِ فَلَمْ يَزَلْ يَقْنُتُ حَتَّى فَارَقَ اَلدُّنْيَا } .‏ 1‏
Ahmad and ad-Daraqutni narrated something similar, adding that he (ﷺ) continued to recite Qunut (supplication in prayer) in the Fajr prayer till he separated from this world.