Farwah bin Nawfal narrated from his father that he went to the Prophet (ﷺ) and said: “O Messenger of Allah, teach me something that I may say when I go to my bed.” So he said: “Recite Qul yā ayyuhal kāfirūn (Sūrat al-Kāfirūn), for verily it is a disavowal from shirk. Reference: Jami` at-Tirmidhi 3403 . In one report, the Prophet ﷺ said: Recite Qul yā ayyuhal kāfirūn (Sūrat al-Kāfirūn) and then sleep upon completion [of its recitation], for it is a disavowal from shirk. Reference: Sunan Abi Dawud 5055 .