What Is Transubstantiation?
Transubstantiation is what separates the Catholics from everyone else. The word means that bread and wine "become" the Body and Blood of Jesus. This is not symbolism, it's a supernatural happening.
This is a Roman Catholic term used to describe what happens to the bread and wine during the celebration of Holy Communion. Transubstantiation means that the bread and wine actually become the body and blood of Christ. They look and taste like bread and wine but have been supernaturally changed into the physical and spiritual essence of Jesus. This is more than just the body and blood, it is the soul and divinity of Christ present in the "host" (the wafer).
This is a key distinctive of Catholic doctrine. The sacrifice of Calvary is renewed every day in the mass by the transubstantiation of bread and wine into Christ's body and blood. The Protestant Church sees the work of the Cross as a finished work, done "once for all". Catholics see the crucifixion as something to be renewed daily and therefore repeat Christ's death once a day. All Priests are required to celebrate mass every day as part of their vows.
In a recent poll of American Catholics, only 30 percent believed that they were actually receiving Christ's body, blood, soul and divinity in Communion. This is what the Church teaches. Many thought that the lements "represented" Christ's body and blood. Some thought that Christ was somehow "in" the elements. Some thought that their personal belief turned the elements into Christ for them. Other denominations teach that the bread and wine "represent" Christ's body and blood, and symbolically partake of it.
Where does this belief come from? Catholics point to John's Gospel: "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) NKJV
Then, in Paul's first letter to the Corinthians: "Therefore whoever eats this bread or drinks this cup of the Lord in an unworthy manner will be guilty of the body and blood of the Lord." "For he who eats and drinks in an unworthy manner eats and drinks judgement to himself, not discerning the Lord's body." (1Cor11: 27,29) NKJV
These passages point to an actual ingestion of The Body and Blood. Many of Jesus' followers could not accept this teaching and stopped following Him. Why? Because of the Jewish ban on drinking blood. To drink blood is definitely not kosher. In Jewish Law all blood must be drained from animals before they can be eaten. That makes it kosher. Jesus did not stop the deserters by saying "It's OK, it's only symbolic". Jesus meant what he said and lost disciples because they could not accept it. "From that time many of His disciples went back and walked with Him no more." (John 6:66) NKJV
How does the transformation of bread and wine into body and blood take place? The bread and wine are "offerings" to God. They are turned into Christ's Body and Blood. It is not the Priest who has this power; the Priest merely says the words at the appointed time. It is God who transforms these offerings and they become Christ's Body, Blood, Soul and Divinity. The miracle of the Incarnation is repeated as Jesus Christ once again takes on human form for our benefit.
This is why Catholics pay the utmost respect to the Tabernacle in the sanctuary. It "contains" the actual body and blood and soul of Jesus. It is why they genuflect when passing in front of the altar in Church. Each partaker is responsible to be prepared to receive the holy emblems. It is why Confession is required before, why fasting is prescribed, why there are admonitions about receiving the bread unworthy. It is a community meal in which believers share Christ's Body and Blood in remembrance and renewal. Christ once again gives His Body, Blood and Self to the congregation. "The Presence" of Christ, body and soul, in the Eucharist is what makes it so special.