There has been a debate in the comments over whether St. Augustine believed that the elements of the Eucharist are transformed into the Body and Blood of Christ. It is also claimed that St. Augustine held to a spiritual presence of Christ akin to that taught by John Calvin.
Concerning the Eucharist, St. Augustine wrote:
"Nobody eats this flesh without previously adoring it."As St. Augustine taught, Catholic Christians bow or kneel before receiving the Eucharist. This is because Catholics show worship or adoration (Greek - latria; Latin - adoratio) to the Eucharist because it is the Body and Blood of Jesus Christ and worthy of our worship.- St. Augustine, Enarr. in Ps. 98, 9
St. Augustine also explained that the Christians of his day prayed for the departed at the Eucharistic liturgy and he referred to the offering of the Eucharist as "the most true sacrifice" (verissium sacrificium) that the priest offers (immolat) to God. (cf. City of God, 10, 20)
Either St. Augustine believed that he was offering the one true Sacrifice of Calvary at the Eucharist or he believed he was offering an independent sacrifice of symbolic bread and wine. A sacrifice to God of symbolic bread and wine would be blasphemous since the only acceptable sacrifice before God is the sacrifice of Christ that was offered once and for all. Therefore, Augustine must have believed that the sacrifice of the Eucharist was the same sacrifice of Christ on the cross. Hence, we have here the Catholic doctrine of the Eucharist.
The Eucharistic sacrifice is NOT a new sacrifice or a repetition of the sacrifice of Christ. It is the one sacrifice that Christ offered once and for all time. The presence of this one sacrifice is eternal and it realized in the eschatological banquet of the Holy Mass. Christ does not die again and again. But that one sacrificial death of redemption is re-presented every time the Holy Mass is offered or, to use the Latin phrase of St. Augustine, immolated.