Ignatius letter to Philedelphia Chapter IV.—Have but one Eucharist, etc.
Take ye heed, then, to have but one Eucharist. For there is one flesh of our Lord Jesus Christ, and one cup to the unity of His blood; one altar. Letter to Smyrna- Some ignorantly deny Him;- Chapter IV.—Beware of these heretics.(Docetists)
I give you these instructions, beloved, assured that ye also hold the same opinions [as I do]. But I guard you beforehand from those beasts in the shape of men, whom you must not only not receive, but, if it be possible, not even meet with;For what does any one profit me, if he commends me, but blasphemes my Lord, not confessing that He was [truly] possessed of a body?if they believe not in the blood of Christ, shall, in consequence, incur condemnation.They have no regard for love; no care for the widow, or the orphan, They are ashamed of the cross; they mock at the passion; they make a jest of the resurrection.=long version. They abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again.=short version. Those, therefore, who speak against this gift of God, incur death…I am the wheat of God, and let me be ground by the teeth of the wild beasts, that I may be found the pure bread of Christ…Take heed, then, often to come together to give thanks to God, and show forth His praise…
David Ruiz: .The context is fighting heresy of those who said Christ died not in the flesh .The Docetists said Christ seemed to die but it was someone else in his place. Ignatius replies that Docetists “seem” to be Christian. Context,context,context .For sure, if like the short version -the Eucharist to be the flesh of Christ" by itself, it is understandable ,as you also take the John 6 and Last Supper words literal , apart from any larger context…Last but not least, most scholars still place these writings almost 100 years after Christ.