Holy Supper (communion).
7- (...) the blood of Jesus Christ his Son cleanseth us from all sin. (1st John 1)
The wine is the blood of the new alliance; depends of two things for remission (absolution) of sins:
1º: repentment (our).
2º: The blood of Christ,who died because of our sins.
Who killed Christ?
Not those of the world! It was the Church itself (those who didn’t repent).
Not only the religious of that time that were guilty, but in every supper we judge, condemn and kill Christ, if there is no repentment. (God was perfect to not condemn only the ones of that time), as Paul spoke in: 1st Cor 11:
27- Wherefore whosoever shall eat this bread, and drink [this] cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord. (Will be guilty of the death of Christ)

28- But let a man examine himself, and so let him eat of [that] bread, and drink of [that] cup. (If is a Christian has to eat)
This is why there has to be preparation (look into oneself and repent before the supper); if you do take the supper (without repentment) is guilty of the death of Christ. If you don´t repent and take the supper, you´ll be denying and rejecting Christ´s sacrifice, and no longer be a Christian.
Heb. 10.26- (...) there remaineth no more sacrifice for sins,
29- Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace? (There is no use Jesus did his part, if we don´t do ours and repent). Paul speaks very clearly what Jesus said when he established the supper in: 1st Cor 11. 23. 26: