(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”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou