Al-Kahf • EN-ASBAB-AL-NUZUL-BY-AL-WAHIDI
﴿ وَيَسْـَٔلُونَكَ عَن ذِى ٱلْقَرْنَيْنِ ۖ قُلْ سَأَتْلُوا۟ عَلَيْكُم مِّنْهُ ذِكْرًا ﴾
“AND THEY will ask thee about the Two-Horned One. Say: "I will convey unto you something by which he ought to be remembered."”
(They will ask thee of Dhu�l-Qarnayn�) [18:83]. Said Qatadah: �The Jews asked the Prophet, Allah bless him and give him peace, about Dhu�l-Qarnayn, and Allah, exalted is He, revealed these verses�.