Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said: One day I was with the Messenger of Allah (peace and blessings be upon him) while he was riding. I placed my hand on his foot and said: "O Messenger of Allah! Teach me to recite something from Surah Hud or Surah Yusuf." The Messenger of Allah (peace and blessings be upon him) said: "O Uqbah bin Amir! You will not recite any surah more beloved to Allah and more eloquent in His sight than Surah al-Falaq. So if you are able not to let it slip from you in any prayer, then do so."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14932