Perhaps this isn't clear, but the best summation of Augustinian thought is not a phrase of Augustine himself but a modern English idiom: You are what you eat. That is, you are moved by what you love and the degree to which you love it, and you then become like it in the same degree that you love it. There was no law of gravitation, so things fell in proportion to weight, and Augustine applied that to love.

So for instance in the Eucharist we love Christ and are moved by our love, which should be above all things, and through grace we become like God, though not substantially of course. (The same is true of eating too much junk food, actually.)

No, I just assumed the OP was referring to a contemporary eucharistic hymn. My way of understanding it comes from a “Duh!” moment I had while reading the first four or so chapters of Confessions, with my teacher explaining his physics. He talks about food a fair bit, so the connection is obvious...

There is also the corporal element. By celebrating and receiving the sacrament, the church becomes more fully what she is already, the Body of Christ.

This is one of the most beautiful of all truths of the Catholic faith.

United to Jesus through faith and love, the communicant “is transformed into him and becomes his member,” says Aquinas, “for this food is not changed into the one who eats it, but turns into itself the one who takes it . . . This is a food capable of making man divine and inebriating him with divinity.”[1] In the Sentences, Thomas simply states: “the proper effect of this sacrament is the conversion of man into Christ, that it might be said with the Apostle, ‘I live, now not I, but Christ lives in me.’”[2]

[1] Super Ioan. 6, lec. 7, §969; cf. ST III, q. 73, a. 3, ad 2. In these places Thomas goes on to cite a passage from the Confessions in which Augustine describes how he heard Christ saying to him: “You will not be changing me into you, as food becomes your flesh; it is rather you who will be changed into me” (Confessions 7.10; cf. Pine-Coffin, 147). Commenting on Ps. 22:5, Aquinas writes: “This [goodly] cup is the gift of divine love which inebriates, since one who is drunk is not in himself . . . for he is made to be in ecstasy”; “the cup means the blood of Christ, which ought to make us drunk” (Super Ps. 22, n. 2).

[2] In IV Sent., d. 12, q. 2, a. 1, qa. 1.

Just as orthodox teaching out of context can be understood in an unorthodox manner, here we have the lowering of God masquerading as orthodox Christian teaching.

It is true that when we receive Christ it is we who are transformed, not Christ.
It is further true that Christ, being God, condescended to be among us and to become food for our souls.

It is nevertheless not true that receiving Christ is, always and everywhere, good for us. St. Thomas Aquinas, echoing St. Paul, tells us that if we receive unworthily, we commit an awful sin against God.

When the Church architecture reminds us of the awesomeness of God, and raises our thought to contemplate the divine, all the teaching advanced that "we become what we receive" is in its proper place. But if the building screams "Bauhaus", and if the faith that Christ is transsubstantially present under the appearance of bread and wine is absent, then "we become what we receive" merely reinforces the anthropocentrality of modern worship.

Exhibit A in this case, in musical terms, is Michael Joncas' ditty "I have loved you with an everlasting love" -- which I have spoofed as "I have loved you with such narcissistic love". Scripture isn't the problem, and neither is the proper exposition of doctrine.

Overheard yesterday: "I can't even remember the last time I left church feeling this guilty."

This series of quotations sounds even more daring than the one from Augustine:

The Word became flesh to make us "partakers of the divine nature":78
"For this is why the Word became man, and the Son of God became the Son of man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God."79
"For the Son of God became man so that we might become God."80
"The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods."81

And to think the editors had the nerve to footnote them all:

78 2 Pt 1:4.
79 St. Irenaeus, Adv. haeres. 3, 19, 1: PG 7/1, 939.
80 St. Athanasius, De inc. 54, 3: PG 25, 192B.
81 St. Thomas Aquinas, Opusc. 57, 1-4.

If anyone wants to investigate this further, here's where I got the list.

On the other hand, to be fair to CGZ, it is possible that someone might present the quotation from Augustine in an exaggerated form: e.g., to suggest that the faithful should give latria one to another; that would be an error.