Question: who are the yajuj and majuj?
Answer: Yajuj and Majuj are the Arabic names for Gog and Magog. Dhu l-Qarnayn directs them to bring pieces of iron, which are melted in a fire to form a wall that can neither be scaled nor pierced, barring the way between two cliffs. This will keep out Yajuj and Majuj until the last days, when they are let loose.