Jerome

And they had four wings, and their wings were joined one to another. They did not turn back when they walked, but each one moved forward before its face. The Gospels are joined to each other and cling together, and they fly to and fro throughout the whole world, running here and there, without end to their flight, never surpassing or receding, but always proceeding to further things. And both Paul and Virgil say: Forgetting the things that are past, and reaching forth towards those things that are still to come. …

Commentary on Ezekiel ↗

Gregory the Dialogist

"And the hand of a man under their wings on four sides." The four parts can be understood in this place as the four regions of the world, namely East, West, South, and North, because the preaching of the saints has gone forth by God's authority into all parts of the world. We can also understand by the four principal parts the four virtues from which the remaining virtues arise, namely prudence, fortitude, justice, and temperance. We truly receive these virtues when we maintain their order. …

Homilies on Ezekiel, Book 1, Homily 3 ↗