كتاب صلاة المسافرين وقصرها
6
The Book of Prayer - Travellers
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Chapter: It is recommended to pray two rak`ah for the sunnah of Fajr. And encouragement to pray them regularly, and to make them brief, and to persist in offering them, and clarifying what is recommended to recite therein
(14)
باب اسْتِحْبَابِ رَكْعَتَيْ سُنَّةِ الْفَجْرِ وَالْحَثِّ عَلَيْهِمَا وَتَخْفِيفِهِمَا وَالْمُحَافَظَةِ عَلَيْهِمَا وَبَيَانِ مَا يُسْتَحَبُّ أَنْ يُقْرَأَ فِيهِمَا
Sahih Muslim 727 a

Ibn 'Abbas reported that the Messenger of Allah (ﷺ) used to recite in first of the two (supererogatory) rak'ahs of the dawn:

"Say: We believed in Allah and what was revealed to us..." verse 136 from Surah Baqara, and in the second of the two: "I believe in Allah and I bear testimony that we are Muslims" (iii. 52).
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا الْفَزَارِيُّ، - يَعْنِي مَرْوَانَ بْنَ مُعَاوِيَةَ - عَنْ عُثْمَانَ بْنِ حَكِيمٍ الأَنْصَارِيِّ، قَالَ أَخْبَرَنِي سَعِيدُ بْنُ يَسَارٍ، أَنَّ ابْنَ عَبَّاسٍ، أَخْبَرَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَقْرَأُ فِي رَكْعَتَىِ الْفَجْرِ فِي الأُولَى مِنْهُمَا ‏{‏ قُولُوا آمَنَّا بِاللَّهِ وَمَا أُنْزِلَ إِلَيْنَا‏}‏ الآيَةَ الَّتِي فِي الْبَقَرَةِ وَفِي الآخِرَةِ مِنْهُمَا ‏{‏ آمَنَّا بِاللَّهِ وَاشْهَدْ بِأَنَّا مُسْلِمُونَ‏}
Reference : Sahih Muslim 727 a
In-book reference : Book 6, Hadith 121
USC-MSA web (English) reference : Book 4, Hadith 1576
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