Sahih Muslim Book - 4, Hadith - 1028

و حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ وَمُحَمَّدُ بْنُ رَافِعٍ وَاللَّفْظُ لِابْنِ رَافِعٍ قَالَا حَدَّثَنَا يَحْيَى بْنُ آدَمَ حَدَّثَنَا زُهَيْرٌ عَنْ سِمَاكٍ قَالَ سَأَلْتُ جَابِرَ بْنَ سَمُرَةَ عَنْ صَلَاةِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ كَانَ يُخَفِّفُ الصَّلَاةَ وَلَا يُصَلِّي صَلَاةَ هَؤُلَاءِ قَالَ وَأَنْبَأَنِي أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يَقْرَأُ فِي الْفَجْرِ بِق وَالْقُرْآنِ وَنَحْوِهَا.

It was narrated that Simak said: "I asked Jabir bin Samurah about the prayer of the Prophet. He said: 'He used to make his prayer short, and he did not pray like these people."' And he told me that the Messenger of Allah (s.a.w) used to recite in Fajr "Qaf. By the glorious Qur'an" and similar Surah.