Justin Martyr

For we do not receive these things as common bread or common drink; but just as our Savior Jesus Christ, being incarnate through the work of God, took flesh and blood for our salvation, so too we have been taught that the food over which thanks have been given by a prayer of the Word that is from Him, from which our flesh and blood are fed by transformation, is both the flesh and blood of that incarnate Jesus. (First Apology 66:2)