Augustine of Hippo — as excerpted in the Catena Aurea on John 6:51

“(Gloss. Nic.) Our Lord pronounces Himself to be bread, not only in respect of that Divinity, which feeds all things, but also in respect of that human nature, which was assumed by the Word of God: And the bread, He says, that I will give is My flesh, which I will give for the life of the world.”