It is narrated from Hazrat Uqbah bin Amir (may Allah be pleased with him) that once I was walking ahead of the Prophet's (peace and blessings be upon him) mount on a path, when suddenly the Prophet (peace and blessings be upon him) said to me, "Shall I not teach you two surahs, the like of which there is none?" I said, "Why not, O Messenger of Allah!" (peace and blessings be upon him). So the Prophet (peace and blessings be upon him) taught me Surah Al-Falaq and Surah An-Naas. Then the prayer was established, the Prophet (peace and blessings be upon him) went forward and recited these two surahs in the Fajr prayer. Then, as he passed by me, he said, "O Uqbah! What do you understand? (Recite these two surahs when you go to sleep and when you wake up as well)."