Traced to Ka'b al-Ahbar (automatic guess): a report of earlier scriptures, not a hadith of the Prophet ﷺ.
المعقل من يأجوج ومأجوج الطور، ومن الملاحم دمشق
The stronghold of Gog and Magog, Al-Tur, and from the epics, Damascus
نعيم ثنا بقيةصفوانكعبautomatic reading, unverified