Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) said: I was walking with the Messenger of Allah (peace and blessings be upon him) when he (peace and blessings be upon him) said to me: "Say, O Uqbah." I said: What shall I say? Then he fell silent. I said to myself: If he repeats it to me, I will say just what he says. He (peace and blessings be upon him) said again: "Say." Then he (peace and blessings be upon him) recited Surah al-Falaq until he completed it. Then the Messenger of Allah (peace and blessings be upon him) said: "No one who asks has ever asked with anything like it, and no one who seeks refuge has ever sought refuge with anything like it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15020
Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) said: I was travelling with the Messenger of Allah (peace and blessings be upon him) between al-Juhfah and al-Abwa' when a windstorm and darkness covered us. The Messenger of Allah (peace and blessings be upon him) began seeking refuge with Surah al-Falaq and Surah al-Nas, and saying: "O Uqbah! Seek refuge, for no one who seeks refuge has ever sought refuge with anything like them." Sayyiduna Uqbah (may Allah be pleased with him) said: Then I heard him (peace and blessings be upon him) leading us in prayer with these two surahs.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15021