Musannaf Ibn Abi Shaybah

Abu Tufail narrates through another chain that Hazrat Ali (may Allah be pleased with him) was asked about Dhu al-Qarnayn, so he replied that he was neither a prophet nor a king, rather he was a righteous servant who was sincere to Allah, so Allah was sincere to him. Thus, he invited his people towards Allah, and he was struck on the right side of his head and died, then Allah brought him back to life. Then he again called his people towards Allah, and again he was struck on the left side of his head and died again, so Allah brought him back to life again. That is why he became famous by the name "Dhu al-Qarnayn."