I was leading the camel of the Messenger of Allah ﷺ during a journey when he said to me, "Uqba, shall I teach you the two best surahs ever recited?"He then taught me, "Say, I seek refuge with the Lord of the daybreak," and "Say, I seek refuge with the Lord of mankind."But he noticed that I was not particularly delighted with them. When he stopped for the dawn prayer, he led the people in the dawn prayer reciting these two surahs. After the Messenger of Allah ﷺ finished the prayer, he turned to me and said, "Uqba, what did you think?"
حدثنا أحمد بن عمرو بن السرح أخبرنا ابن وهب أخبرني معاوية عن العلاء بن الحارث عن القاسم مولى معاوية
كنت أقود برسول الله ﷺ ناقته في السفر فقال لي يا عقبة ألا أعلمك خير سورتين قرئتا فعلمني قل أعوذ برب الفلق وقل أعوذ برب الناس قال فلم يرني سررت بهما جدا فلما نزل لصلاة الصبح صلى بهما صلاة الصبح للناس فلما فرغ رسول الله ﷺ من الصلاة التفت إلي فقال يا عقبة كيف رأيت
[Its isnad is hasan] Nasai reported it in "Al-Istiadhah," in the chapter on what has been mentioned regarding the two surahs of Muawwidhatayn, no. 5438, from Ahmad bin Amr bin Sarh, through this route, and Ibn Khuzayma graded it sahih, no. 535.