“Barangsiapa yang membaca surat Al Kahfi pada hari Jum’at, dia akan disinari cahaya di antara dua Jum’at.” (HR. An Nasa’i dan Baihaqi. Syaikh Al Albani mengatakan bahwa hadits ini shohih sebagaimana dalam Shohihul Jami’ no. 6470)
How many people are heedless of the practice of this one when the night Friday or Friday, namely, reading surat Al Cave.
Or maybe some people haven't learned this practice. But read surat Al-Cave is a recommended (mustahabb) on Friday because the reward is so great as the news was reported by the righteous and carry the correct teaching of IE the Prophet alaihi wa sallam.
Ahaadeeth which discuss this we bring most on this short post. May be useful.