مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 865
Prayer
What is Recited During the Prayer - Section 3
وَعَنْ عَبْدُ اللَّهِ بْنِ عَامِرِ بْنِ رَبِيعَةَ قَالَ: صلينَا وَرَاء عمر ابْن الْخطاب الصُّبْح فَقَرَأَ فيهمَا بِسُورَةِ يُوسُفَ وَسُورَةِ الْحَجِّ قِرَاءَةً بَطِيئَةً قِيلَ لَهُ: إِذًا لَقَدْ كَانَ يَقُومُ حِينَ يَطْلُعُ الْفجْر قَالَ: أجل. رَوَاهُ مَالك
‘Amir b. Rabi'a said that they prayed the morning prayer behind ‘Umar b. al-Khattab and that he recited slowly in both rak'as Sura Yusuf and Sura al-Hajj (Al-Qur’an; 22). When someone remarked that he must have begun the prayer at break of day he replied that that was so. Malik transmitted it.
Mishkat al-Masabih, 865صَحِيح (الألباني)