Oecumenius

And, he says, the kings of the earth and the great men and the commanders and the rich and the powerful and every slave and free man hid themselves in the caves and among the rocks of the mountains; and they said to the mountains and to the rocks, "Fall on us and hide us from the face of Him who sits on the throne and from the wrath of the Lamb, for the great day of their wrath has come, and who can stand?" Kings again and great men, commanders and the rich and powerful, he calls wretched demons, as those who began to oppress the …

Commentary on Revelation ↗

Bede

They hid in caves and among the rocks of the mountains, etc. When the weaker ones seek to be strengthened by the examples of the high ones in the Church, to be fortified by their advice, and to be protected by their warnings and prayers, they figuratively ask these mountains to fall on them through their compassionate affection. For the high mountains are a refuge for the deer, and the rocks a shelter for the hedgehogs (Ps. 104:18).

Commentary on Revelation ↗

Alcuin of York

And the kings of the earth, and the princes, and tribunes, and the rich, and the strong, and every bondman, and every freeman, hid themselves in the dens and in the rocks of mountains. The kings are those who govern themselves well. Likewise for the princes, who do not resist vices as well as the kings, but still do so as they can. Likewise, the tribunes have still less power than the princes, but they too nonetheless resist the Devil as they can. …

Commentary On Revelation ↗