From Ignatius to the Smyrnaeans warning against Doecetic practice:
"7 They abstain from Eucharist and prayer because they do not acknowledge that the Eucharist is the flesh of our Savior Jesus Christ which suffered for our sins, which the Father raised up by his goodness. Those who deny God's gift are dying in their squabbles; it would be better for them to love so that they may rise..."
"The Apostolic Fathers, Modern Translations of These Early Christian Writings", ed Jack N. Sparks", 1978, Thomas Nelson, Nashville.
I have will be ordering soon the works above translated by Kirsopp Lake (Loeb Classical Library), as these seem to be held in high regard by scholars and theologians.