“Abu Sa’īd al-Khudri reports that the Prophet (pbuh)said:
Whoever recites Sūrah al-Kahf on Jumu’ah (i.e., ‘Friday’ of the pagan world) will have illumination from the light (of the Sūrah) from one Jum’ah to the next.”
In another hadith
“Ibn ‘Umar reports that the Prophet (pbuh) said:
Whoever recites Sūrah al-Kahf on Jumu’ah will be blessed with a light that will rise from underneath his feet to the peak of the sky. This will be a light for him on the Day of Resurrection, and he will be forgiven for what is between the Jumu’ah, i.e., or the day of the congregational prayers [and the next] Jumu’ah. “