Sahih al-Bukhari 758
Sahih al-Bukhari · Book 10: Call to Prayers (Adhaan) · Recitation of the Qur'an (Surat Al-Fatiha) is compulsory for the Imam and the followers, at the home and on journey, in all As-Salat (the prayers) whether the recitation is done silently or aloud.
Narrated Jabir bin Samura:
حَدَّثَنَا أَبُو النُّعْمَانِ ، حَدَّثَنَا أَبُو عَوَانَةَ ، عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ ، عَنْ جَابِرِ بْنِ سَمُرَةَ ، قَالَ قَالَ سَعْدٌ كُنْتُ أُصَلِّي بِهِمْ صَلاَةَ رَسُولِ اللَّهِ صلى الله عليه وسلم صَلاَتَىِ الْعَشِيِّ لاَ أَخْرِمُ عَنْهَا، أَرْكُدُ فِي الأُولَيَيْنِ وَأَحْذِفُ فِي الأُخْرَيَيْنِ. فَقَالَ عُمَرُ ـ رضى الله عنه ـ ذَلِكَ الظَّنُّ بِكَ .
Sa`d said, "I used to pray with them a prayer similar to that of Allah's Messenger (ﷺ) (the prayer of Zuhr and `Asr) reducing nothing from them. I used to prolong the first two rak`at and shorten the last two rak`at." `Umar said to Sa`d "This was what we thought about you."