I think the worst thing that a protestan can do is to quote books of the church fahters to defend their believes because they were totally against the stuffs they believe.
About the eucarist:
St Ignatious of Antioch disciple of st John
Epistle to the philipians
Chapter 4. Have but one Eucharist,
Take heed, then, to have but one Eucharist. For there is one flesh of our Lord Jesus Christ, and one cup to [show forth] the unity of His blood; one altar; as there is one bishop, along with the presbytery and deacons, my fellow-servants: that so, whatsoever you do, you may do it according to [the will of] God.
St Cyril of Jerusalem
On the Body and Blood of Christ
Justin Martyr
first apology
Chapter 66. Of the Eucharist.
And this food is called among us Εὐχαριστία [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh. For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, “This do in remembrance of Me, Luke 22:19 this is My body;” and that, after the same manner, having taken the cup and given thanks, He said, “This is My blood;” and gave it to them alone. Which the wicked devils have imitated in the mysteries of Mithras, commanding the same thing to be done. For, that bread and a cup of water are placed with certain incantations in the mystic rites of one who is being initiated, you either know or can learn.
The Church Fathers used to defend everyone of the catholic doctrines.
They even refered themselves as being catholics on their books.