From Matthew 26
27 And he took a cup, and when he had given thanks he gave it to them, saying, Drink of it, all of you; 28 for this is my blood of the covenant, which is poured out for many for the forgiveness of sins. 29 I tell you I shall not drink again of this fruit of the vine until that day when I drink it new with you in my Fathers kingdom.
Jesus clearly referred to the contents of the cup as 'fruit of the vine'. Grapes grow on a vine...sounds like wine.
There it is. Simple - 3 verses. No assumptions, laid out by Jesus Himself. Jesus gave His disciples wine in the cup that He described as 'His blood'.
Are we ready to move on to 'the body' yet?
Exactly. Bread turned into his flesh, wine turned into his blood so future generations can follow his commands.
Simple, when you don't underestimate the power of God.
You neglected to read this comment.
I also wonder how transubstantiation, while not mentioned specifically, can be the hard truth, yet Matthew 23 has this: 9 And do not call anyone on earth father, for you have one Father, and he is in heaven.
I believe the Catholic Church has done more to bring souls to God, but I also believe they get so hung up in the religion/theological etudes that they often miss the mark by diverting attention from the spiritual to the canons and doctrines.