When it comes to the doctrine of substantiation there’s simply no substance … only a substantial error.
If any tradition causes us to believe that John 6:51-56 teaches that Christians literally eat the flesh and drink the blood of Jesus then it’s the tradition that has the problem because the literal doctrine of transubstantiation literally violates the doctrine of God.
If for no other reason, the error of transubstantiation can be plainly seen by realizing that God has always told his people that consuming blood is sinful – and if God refused to allow his people to consume the blood of an earthly animal then how much more distasteful is the thought of pleasing God by literally consuming the blood of the heavenly Lamb of God (Genesis 9:4, Leviticus 17:10-14, Acts 15:28-29; 21:25).
By partaking of a physical communion we no more drink the literal blood of Jesus than we are literally washed in the blood of Jesus when we are submersed in the watery grave of baptism (Acts 2:38; 22:16, Romans 6: 4-7, Revelation 1:5). Obedience to the physical act of communion’s memorial reaps the spiritual reward of the obedience that remembered us in his desire for communion (Matthew 26:26-28, Hebrews 5:8-9). Jesus did not and does not literally consume his own blood and neither do Christians!
The Bible teaches us that the blood of Jesus transfers, not transubstantiates, his righteousness upon and within us by faith (Romans 3:25; 2 Corinthians 5:21, Colossians 2:12), so beware of consuming anyone’s doctrine who teaches otherwise!
“But any sin offering from which some of its blood is brought into the Meeting Tent to make atonement in the sanctuary must not be eaten. It must be burned up in the fire.” (Leviticus 6:30 NET)