The Church fathers (writing post New Testament) affirm the apostolic faith in the real presence of Christ in the Eucharist.
Recognize in this bread what hung on the cross,
and in this chalice what flowed from his side.
St Augustine of Hippo
I have no taste for the food that perishes nor for the pleasures of this life. I want the bread of God, which is the flesh of Christ, who was the seed of David; and for drink I desire his blood which is love that cannot be destroyed.
St Ignatius of Antioch
The flesh feeds on the body and blood of Christ,
that the soul likewise may be filled with God.
Tertullian
Our bodies, having received the Eucharist, are no longer corruptible, because they have the hope of the resurrection.
St Irenaeus of Lyons
Without shame and without doubt, eat the flesh and drink the blood of Christ, if you are desirous of true life.
St Gregory of Nazianzus
We must always bear in mind that the
Eucharist is not something we do.
It is not our own commemoration
of what Jesus said and did.
No. It is precisely an act of Christ!
It is Christ who acts there, who is on the altar.
It is a gift of Christ, who makes himself present
and gathers us around him,
to nourish us with his Word and with his life.
General Audience Pope Francis 12 Feb 2014