Augustine of Hippo

..."And He fed them of the fat of wheat, and from the rock with honey He satisfied them." In the wilderness from the rock He brought forth water, not honey. "Honey" is wisdom, holding the first place for sweetness among the viands of the heart. How many enemies of the Lord, then, that lie unto the Lord, are fed not only of the fat of wheat, but also from the rock with honey, from the wisdom of Christ? …

On the Psalms, Psalm 81 ↗

Jerome

And he fed them from the fat of the wheat. He led them into the land of promise: he fed them not with manna, as in the desert, but with the wheat that fell, that rose again. And he fed them from the fat of the wheat. See the mystery of the Scriptures. From the fat of the wheat. Does wheat have fat? does it perhaps even have entrails? But he wished to show the bounty and richness of spiritual grace, and therefore he named it 'fat.' And with honey from the rock he satisfied them. …

Homily 13, on Psalm 80 ↗

Bonaventure

As inducing strength, the seven virtues are represented by the seven loaves of the gospel, from which the whole body of the elect is fed. For the philosophers, these four virtues became stones, but they are actually seven breads of life. Moses' five loaves were made of barley, but the seven loaves of wheat of the evangelical teaching were made out of the fat of the wheat.

Collations on the Hexaemeron, Collation 7 ↗