When you finish the sunset prayer, say: 'O Allah, protect me from Hell" seven times; for if you say that and die that night, protection from it would be recorded for you; and when you finish the dawn prayer, say it in a similar way, for if you die that day, protection from it would be recorded for you. AbuSa'id told me that al-Harith said: The Messenger of Allah (ﷺ) said this to us secretly, so we confine it to our brethren.
Sunan Abi Dawud Book 43, Hadith 307
← Previous Hadith The Prophet (ﷺ) said: If anyone says in the morning: "O Allah! in the morning we call Thee, the bearers of Thy Throne, Thy angels, and all Thy creatures to witness that Thou art Allah than Whom there is no god, Thou being alone and without a partner, and that Muhammad is Thy servant and Thy Apostle," Allah will forgive him any sins that he commits that day; and if he repeats them in the evening. Allah will forgive him any sins he commits that night.

Sunan Abi Dawud Book 43, Hadith 306 Next Hadith → A similar tradition (to No. 5061) has been transmitted by Muslim ibn al-Harith ibn Muslim at-Tamimi on the authority of his father from the Prophet (ﷺ) through a different chain of narrators, up to "protection from it".

But this version says: "before speaking to anyone". In this version Ali ibn Sahl said that his father told him.

Ali and Ibn al-Musaffa said: The Messenger of Allah (ﷺ) sent us on an expedition. When we reached the place of attack, I galloped my horse and outstripped my companions, and the people of that locality received me with a great noise.

I said to them: Say "There is no god but Allah," and you will be protected. They said this.

My companions blamed me, saying: You deprived us of the booty. When we came to the Messenger of Allah (ﷺ), they told him what I had done.

So he called me, appreciating what I had done, and said: Allah has recorded for you so and so (a reward) for every man of them.

AbdurRahman said: I forgot the reward. The Messenger of Allah (ﷺ) then said: I shall write a will for you after me. He did this and stamped it, and gave it to me, saying....He then mentioned the rest of the tradition to the same effect. Ibn al-Musaffa said: I heard al-Harith ibn Muslim ibn al-Harith at-Tamimi transmitting it from his father.

Sunan Abi Dawud Book 43, Hadith 308