Mishkat al-Masabih 4 Prayer كتاب الصلاة 254

وَعَنْ أَبِي قَتَادَةَ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يقْرَأ فِي الظُّهْرِ فِي الْأُولَيَيْنِ بِأُمِّ الْكِتَابِ وَسُورَتَيْنِ وَفِي الرَّكْعَتَيْنِ الْأُخْرَيَيْنِ بِأُمِّ الْكِتَابِ وَيُسْمِعُنَا الْآيَةَ أَحْيَانًا وَيطول فِي الرَّكْعَة الأولى مَا لَا يطول فِي الرَّكْعَةِ الثَّانِيَةِ وَهَكَذَا فِي الْعَصْرِ وَهَكَذَا فِي الصُّبْح

Abu Qatada said that in the first two rak’as of the noon prayer the Prophet used to recite Umm al-Kitab and two suras , and in the last two rak’as Umm al-Kitab , and he would sometimes recite loud enough for them to hear the verse. He would prolong the first rak’a more than the second; and he acted similarly in the afternoon and the Morning Prayer. (Bukhari and Muslim.)