At the last supper, all 12 disciples were there for the bread and the cup:

Luke 22:19 And he took bread, and gave thanks, and brake it, and gave unto them, saying, This is my body which is given for you: this do in remembrance of me.

  21 But, behold, the hand of him that betrayeth me is with me on the table.

So, Judas was partaking with them.

Could that have been the most extreme example of:

I Corinthians 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.

  29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord’s body.

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