Quran 18:94 — The Cave (Al-Kahf)

They said, "O Zul-Qarnain, Gog and Magog are corruptors of the earth. Can we pay you to create a barrier between us and them?"

[18:93] When he reached the valley between two palisades, he found people whose language was barely understandable.

[18:95] He said, "My Lord has given me great bounties. If you cooperate with me, I will build a dam between you and them.