Musnad Ahmad 339:1

Muhammad ibn Ja’far narrated to us, he said: Shu’bah narrated to us, from Yahya ibn Sa’id, from Muhammad ibn Hibban, from al-Walid ibn al-Walid, that he said: "O Messenger of Allah, I feel loneliness." He said: "When you take to your bed, say: 'I seek refuge in the perfect words of Allah from His anger, His punishment, the evil of His servants, and from the incitements of the devils and that they should be present.' For it will not harm you, and it is likely that they will not approach you."