Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said: I followed the Messenger of Allah (peace and blessings be upon him) while he was riding. I placed my hand on his foot and said: "Teach me to recite something from Surah Hud or Surah Yusuf." He (peace and blessings be upon him) said: "You will not recite anything more eloquent in the sight of Allah than Surah al-Falaq."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14931