Abū Saʿīd al-Khudrī reported that the Messenger of Allāh ﷺ said:

“Whoever reads Sūrah al-Kahf as it was revealed, he will have a light on the Day of Resurrection from his standing place to Makkah, and whoever reads ten verses from its end, and then the Dajjāl (False Messiah) emerges, he will not be overpowered, and whoever performs ablution and then says:

سُبْحَانَكَ اللَّهُمَّ وَبِحَمْدِكَ لَا إِلٰهَ إِلَّا أَنْتَ أَسْتَغْفِرُكَ وَأَتُوبُ إِلَيْكَ

‘Far removed are You, O Allāh, from every imperfection, and praise be to You, there is no deity worthy of worship except You, I seek Your forgiveness and repent to You’

[It] will be written on a parchment and then sealed with a seal, and it will not be broken until the Day of Resurrection.”

Reported by al-Ḥākim.

Ṣaḥīḥ li Ghayrih: al-Ḥākim (2097) ed. al-Risālah, and in authentic mawqūf form in Ibn Abī Shaybah (19) ed. al-Shithrī. See: al-Albānī’s Ṣaḥīḥ al-Targhīb wa al-Tarhīb (1473).