How can I explain to my Protestant friends my Coptic Church's view on the Holy Eucharist?
The fact that the Eucharist is really the Holy Body and the Blood of our Lord Jesus Christ is biblical; as it is clearly written in John 6:51-67. On many occasions, our Lord spoke in signs and parables; but we see Him, here, being very clear in saying literally, "the bread that I shall give is My flesh." When the Jews could not believe Him, "The Jews therefore quarreled among themselves, saying, "How can this Man give us His flesh to eat?" (John 6:52) our Lord didn't try to explain that this is only a symbol or that He meant it as a figure of speech. On the contrary, He answered with great solemnity affirming that to eat His real Flesh and drink His Blood is indispensable "Then Jesus said to them, Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you. Whoever eats My flesh and drinks My blood has eternal life, and I will raise him up at the last day. For My flesh is food indeed, and My blood is drink indeed. He who eats My flesh and drinks My blood abides in Me, and I in him" (John 6:53-56). For Him this was not a subject for dispute or argument. This is the true doctrine to the point that when many of His disciples, after having heard this, had left Him; He didn't try to soften His position to bring them back. On the contrary, He turned to His disciples saying, "Do you also want to go away?" (John 6:67). If these are our Lord's own words; we have to believe them. Otherwise, we would be making Him a liar. Now the question arises: How do the bread and wine become Flesh and Blood? The answer is through the Holy Spirit in a mystical way. That is why we call it a Mystery or Sacrament.