He came to the Prophet and said: “O Messenger of Allah, teach my something that I may say when I go to my bed.” SO he said: “Recite: Say: ‘O you disbelievers’ for verily it is a disavowal of Shirk.”Shu’bah said: “Something he would say: ‘One time’ and sometime he would not say it.

“The Prophet would not sleep until he reached Tanzil as-Sajdah and Tabarak.”