False in every respect are those who despise the entire dispensation of God, and deny the salvation of the flesh, and treat with contempt its regeneration, maintaining that it is not capable of incorruption. But if the body indeed does not attain salvation, then neither did the Lord redeem us with His blood, nor is the cup of the Eucharist the communion of His blood, nor the bread which we break the communion of His body. For blood can only come from veins and flesh, and whatsoever else makes up the substance of man—which the Word of God was actually made. By His own blood he redeemed us, as also His apostle declares, “In whom we have redemption through His blood, the forgiveness of sins.” And as we are His members, we are also nourished by means of the creation (and He Himself grants the creation to us, for He causes His sun to rise, and sends rain when He wills). He has acknowledged the cup (which is a part of the creation) as His own blood, from which He moistens our blood; and the bread (also a part of the creation) He has established as His own body, from which He gives increase to our bodies.
St. Irenaeus of Lyons, Against Heresies, Book V, Chapter II