What are the virtues of Surat Al-Kahf, and is it true that whoever recites it for the sake of Allah will have their sins forgiven?

Many hadiths have been narrated regarding the virtues of Surat Al-Kahf, some authentic and others not. It has been reported that it is a protection from the tribulation of the Dajjal, a light for its reciter, a protection from every tribulation for eight days for one who recites it on Friday, and a safeguard from Satan. As for the hadith you mentioned, it has not been found.