Everywhere — starting with Christ’s own words. At the Last Supper He took bread and said “Take ye, and eat. This is my body,” and of the cup, “This is my blood of the new testament” (Matthew 26:26–28). Protestants answer that He meant it symbolically, as when He called Himself a “door” or a “vine.” That is a fair challenge — so look at how Jesus Himself handled exactly that objection.

In John 6 He says, “my flesh is meat indeed, and my blood is drink indeed” (John 6:55). His hearers are scandalized — “How can this man give us his flesh to eat?” — and many disciples walk away. This is the one moment where Jesus lets followers leave over what could be a misunderstanding, and instead of calling them back with “wait, it is only a symbol,” He turns to the Twelve and asks if they will go too. A teacher does not let disciples abandon Him over a metaphor they took too literally. (And the “flesh profiteth nothing” of verse 63 is about the carnal way of thinking — He has just called His flesh “meat indeed.”)

St. Paul read it the same way. He warns that whoever eats the bread or drinks the cup unworthily is “guilty of the body and of the blood of the Lord” and eats judgment on himself for “not discerning the body” (1 Corinthians 11:27–29). You cannot be guilty of profaning a symbol, and no one is judged for failing to “discern” what was never there. Paul’s argument only works if the bread and cup truly are the body and blood.

And the first Christians were unanimous. Around the year 107 — within a decade of the last Apostle — St. Ignatius of Antioch identifies heretics precisely because “they confess not the Eucharist to be the flesh of our Saviour Jesus Christ.”1 For fifteen centuries no Christian body denied the Real Presence; the symbol-only reading is the latecomer. (This is also why the priesthood2 matters: the sacrament is confected by a validly ordained priest in unbroken succession from the Apostles.) The full scriptural and patristic case runs verse by verse and Father by Father.