Augustine on Eating and Drinking Christ's Flesh and Blood

The comments of Augustine, the bishop of Hippo (354-430), on the eating and drinking of Christ's flesh and blood in John 6, sound quite Reformed. Consider these quotes:

“For to believe in him is to eat the living bread. He who believes eats; he is nourished invisibly because he is reborn invisibly. He is an infant within; he is new within. Where he is renewed, there he is sated.”
(Augustine, Tractate 26, on John 6:41-59)

“Therefore, to eat that food and to drink that drink is to abide in Christ and to have him abiding in oneself. And, as a result, he who does not abide in Christ and in whom Christ does not abide, beyond doubt neither eats his flesh nor drinks his blood, but rather eats and drinks the sacrament of so great a thing to judgment for himself, because he presumed to approach unclean to the sacraments of Christ which one takes worthily only if he is clean.”
(Augustine, Tractate 26, on John 6:41-59)

“For they thought that he was going to disburse his body; but he said that he was going to ascend to heaven, whole, of course. ‘When you see the Son of man ascending where he was before,’ surely then, at least, you will see that he does not disburse his body in the way in which you think; surely then, at least, you will understand that his grace is not consumed in bite-sized pieces.”
(Augustine, Tractate 27, John 6:60-72)

“Scripture says, ‘Unless you eat the flesh of the Son of Man and drink his blood, you will not have life in you’ (John 6:54). This appears to enjoin wickedness or wrongdoing, and so it is figurative, a command to participate in the Lord’s passion and to store in our memory the pleasurable and useful knowledge that his flesh was crucified and wounded for our sake.”
(Augustine, On Christian Teaching)