The Catholic Encyclopedia:
“Regarding tradition, the earliest witnesses, as Tertullian and Cyprian, could hardly have given any particular consideration to the genetic relation of the natural elements of bread and wine to the Body and Blood of Christ, or to the manner in which the former were converted into the latter; for
even Augustine was deprived of a clear conception of Transubstantiation, so long as he was held in the bonds of Platonism.”
newadvent.org/cathen/05573a.htm
Susan, I may be corrected here but I’m not aware of St. Augustine articulating a metaphysical explanation of HOW the bread and wine become the body and blood of Christ. He simply professes, and uses scripture (which is very Augustine) in stating that it IS.
Keep in mind that he was a wayward Catholic, who became a Manichaean for 9 years, all the while he continued searching for the truth, even if held in secret. Arriving in Milan, he was profoundly influenced by St. Ambrose. Here’s some Eucharistic words from Ambrose as well.
“Perhaps you will say, ‘I see something else, how is it that you assert that I receive the Body of Christ?’ And this is the point which remains for us to prove. And what evidence shall we make use of? Let us prove that this is not what nature made, but what the blessing consecrated, and the power of blessing is greater than that of nature, because by blessing nature itself is changed…The Lord Jesus Himself proclaims: ‘This is My Body.’ Before the blessing of the heavenly words another nature is spoken of, after the consecration the Body is signified. He Himself speaks of His Blood. Before the consecration it has another name, after it is called Blood. And you say, Amen, that is, It is true. Let the heart within confess what the mouth utters, let the soul feel what the voice speaks.” Ambrose, On the Mysteries, 9:50 (A.D. 390-391).
"Then He added: ‘For My Flesh is meat indeed, and My Blood is drink [indeed].’ Thou hearest Him speak of His Flesh and of His Blood, thou perceivest the sacred pledges, [conveying to us the merits and power] of the Lord’s death, and thou dishonourest His Godhead. Hear His own words: ‘A spirit hath not flesh and bones.’ Now we, as often as we receive the Sacramental Elements, which by the mysterious efficacy of holy prayer are transformed into the Flesh and the Blood, “do show the Lord’s Death.’” Ambrose, On the Christian Faith, 4, 10:125 (A.D. 380).
“Perhaps you will say, ‘I see something else, how is it that you assert that I receive the Body of Christ?’ And this is the point which remains for us to prove. And what evidence shall we make use of? Let us prove that this is not what nature made, but what the blessing consecrated, and the power of blessing is greater than that of nature, because by blessing nature itself is changed…The Lord Jesus Himself proclaims: ‘This is My Body.’ Before the blessing of the heavenly words another nature is spoken of, after the consecration the Body is signified. He Himself speaks of His Blood. Before the consecration it has another name, after it is called Blood. And you say, Amen, that is, It is true. Let the heart within confess what the mouth utters, let the soul feel what the voice speaks.” Ambrose, On the Mysteries, 9:50 (A.D. 390-391).
Note, I’m just finishing a class on St. Augustine at, coincidentally, the Augustine Institute. He had his hands full not only with the Manichaean’s but the Donatists (who threatened him) and the Pelagians as well.
Add in Arianism, and one can see a lot of 4th century heresies which tore at the faithful but were eventually, defeated. All the more reason to believe in Christ’s promise: to lead his Church to all truth, to be with it until the end of time, never allowing the gates of hell to prevail.