Mishkat al-Masabih 848
‘Uqba b. ‘Amir said:
When I was leading God’s Messenger’s she-camel for him on a journey he said to me, “Shall I not teach you, ‘Uqba, the best two suras to recite?” Then he taught me “Say, I seek refuge in the Lord of the dawn” and “Say, I seek refuge in the Lord of men” (Al-Qur’an; 113-114). He saw that I was not greatly pleased with them, so when he alighted for the Morning Prayer he used them in leading the people in the Morning Prayer, and when he had finished he turned to me and said, “How do you find them now, ‘Uqba?” 

Ahmad, Abu Dawud and Nasa’i transmitted it.
وَعَنْ عُقْبَةَ بْنِ عَامِرٍ قَالَ: كُنْتُ أَقُودُ لِرَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَاقَتَهُ فِي السَّفَرِ فَقَالَ لِي: «يَا عُقْبَةُ أَلَا أُعَلِّمُكَ خَيْرَ سُورَتَيْنِ قُرِئَتَا؟» فَعَلَّمَنِي (قُلْ أَعُوذُ بِرَبّ الفلق)
و (قل أَعُود بِرَبّ النَّاس)
قَالَ: فَلَمْ يَرَنِي سَرَرْتُ بِهِمَا جَدًّا فَلَمَّا نَزَلَ لِصَلَاةِ الصُّبْحِ صَلَّى بِهِمَا صَلَاةَ الصُّبْحِ لِلنَّاسِ فَلَمَّا فَرَغَ الْتَفَتَ إِلَيَّ فَقَالَ: «يَا عُقْبَةَ كَيْفَ رَأَيْتَ؟» . رَوَاهُ أَحْمَدُ وَأَبُو دَاوُد وَالنَّسَائِيّ