Musannaf Ibn Abi Shaybah

Hazrat Ibn Sabit narrates that Hazrat Khalid bin Waleed could not sleep at night, so the Holy Prophet (peace and blessings be upon him) said to him: "Shall I not teach you some words, when you say them you will fall asleep? Recite these words: O Allah! Lord of the seven heavens and all that they shade, and Lord of the seven earths and all that they carry, and Lord of the devils and all whom they mislead, be my protector from the evil of all Your creation, lest any of them oppress or transgress against me. Your protection is supreme, and there is no deity except You."