Sayyiduna Mu'adh bin Anas (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) said: "Whoever recites the beginning and the end of Surat al-Kahf, it will be a light for him from his feet to his head; and whoever recites the whole surah, it will be a light for him (filling the space) between the earth and the sky."
Ahmad and al-Tabarani recorded it. The chain of Ahmad contains a narrator, Ibn Lahi'ah, who is da'if (weak), and his hadith has been graded hasan.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب التفسير / 11144
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (197/20) اخرجه احمد فى المسند (439/3) ، أخرجه مسند أحمد برقم: 15199»