Musnad Ahmad Hadith 6696

It is narrated from Ibn Amr (may Allah be pleased with him) that the Noble Prophet (ﷺ) used to teach us these words to recite when frightened during sleep: "I seek refuge in Allah, by all His attributes, from His wrath, His punishment, and from the evil of His servants. I also seek refuge in Allah from the whispers of the devils and from their coming near me." And Abdullah bin Amr (may Allah be pleased with him) himself used to teach this supplication to his children who had reached the age of maturity to recite at bedtime, and for the younger children who could not memorize it, he would write it and hang it around their necks.