Sahih al-Bukhari 776
Sahih al-Bukhari · Book 10: Call to Prayers (Adhaan) · To recite only Surah Al-Fathiha in the last two Rak'a during a four Rak'a Salat (prayer)
Narrated `Abdullah bin Abi Qatada:
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ ، قَالَ حَدَّثَنَا هَمَّامٌ ، عَنْ يَحْيَى ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ ، عَنْ أَبِيهِ ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَقْرَأُ فِي الظُّهْرِ فِي الأُولَيَيْنِ بِأُمِّ الْكِتَابِ وَسُورَتَيْنِ، وَفِي الرَّكْعَتَيْنِ الأُخْرَيَيْنِ بِأُمِّ الْكِتَابِ، وَيُسْمِعُنَا الآيَةَ، وَيُطَوِّلُ فِي الرَّكْعَةِ الأُولَى مَا لاَ يُطَوِّلُ فِي الرَّكْعَةِ الثَّانِيَةِ، وَهَكَذَا فِي الْعَصْرِ وَهَكَذَا فِي الصُّبْحِ.
My father said, "The Prophet (ﷺ) uses to recite Al-Fatiha followed by another Sura in the first two rak`at of the prayer and used to recite only Al-Fatiha in the last two rak`at of the Zuhr prayer. Sometimes a verse or so was audible and he used to prolong the first rak`a more than the second and used to do the same in the `Asr and Fajr prayers."