Theophylact of Ohrid

He calls Himself the true bread, because the only-begotten Son of God, made man, was principally signified by the manna. For manna means literally, what is this? The Israelites were astonished at first on finding it, and asked one another what it was. And the Son of God, made man, is in an especial sense this mysterious manna, which we ask about, saying, What is this? How can the Son of God be the Son of man? How can one person consist of two natures?

Catena Aurea by Aquinas ↗

Thomas Aquinas

But it seems foolish to ask for a miracle for this reason, for Christ had just performed some in their presence which could lead them to believe, as multiplying the bread and walking on the water. What they were asking was that our Lord always provide them with food. This is clear because the only sign they mention is the one given by Moses to their ancestors for forty years, and they ask in this way that Christ always provide food for them. Thus they say: Our fathers ate manna in the desert. …

Commentary on John ↗

Bonaventure

"Our fathers ate manna in the desert," not barley bread, but heavenly bread; whence they also add: "As it is written: He gave them bread from heaven to eat." It is written in the Psalm: "Man ate the bread of Angels; he sent them provisions in abundance." Thus they were puffed up about the miracle shown to their fathers, despising the miracle of Christ; and the Lord humbles them by showing that that Scripture was not fulfilled through Moses, but is fulfilled through himself.

Commentary on John, Chapter 6 ↗

Alcuin of York

And to exalt the miracle of the manna, they quote the Psalm, As it is written, He gave them bread from heaven to eat.

Catena Aurea by Aquinas ↗