´It was narrated from 'Uqbah bin 'Amir that :` He asked the Messenger of Allah [SAW] about Al-Mu'awwidhatain. 'Uqbah said: "The Messenger of Allah [SAW] recited them when he led us in Salah Al-Ghadah (As-Subh)."
Explanation & Benefits
Hafiz Muhammad Ameen
In the morning prayer (Fajr), reciting at length is Sunnah. This was the practice of the Prophet sallallahu alayhi wa sallam; however, on that day, reciting these two short surahs in the morning prayer was to demonstrate their significance—that despite being brief, they are very comprehensive and virtuous, to the extent that they can suffice in place of lengthy recitation in the morning prayer.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 5436