Ambrose of Milan

The wheel within a wheel is life under the law, life under grace; inasmuch as Jews are within the church, the law is included in grace. For one is within the church who is a Jew secretly; and circumcision of the heart is a sacrament within the church. But that Jewish people are within the church of which it is written: "In Judah is God known"; therefore as wheel runs within wheel, in the same way the wings were still and the wings were flying.

On the Holy Spirit 3.21.162 ↗

Gregory the Dialogist

Rightly are the sacred utterances said to be similar to the vision of the sea, because in them there are great volumes of sentences, heaps of meanings. Nor is it undeservedly that Sacred Scripture is said to be similar to the sea, because the sentences of speech are confirmed in it through the sacrament of baptism. Or certainly it must be considered that we sail by ships into the sea when we proceed toward desired lands. But what is in our desire except that land about which it is written: "My portion is in the land of the living"? …

Homilies on Ezekiel, Book 1, Homily 6 ↗

Bonaventure

Ezechiel beheld within figures resembling four living creatures, and later there appeared a wheel within another. Then the Prophet says that "the appearance of the wheels and the work of them was like the appearance of the sea," and that it was "as it were a wheel in the midst of a wheel." According to Gregory, the "two wheels" having "four faces" point to Scripture which has the Old and the New Testaments, the "four faces" being the four principal interpretations, the literal, the figurative, the moral and the anagogical. …

Collations on the Hexaemeron, Collation 13 ↗