The chapters and verses were never in the original documents, but were added much later by an English monk, as I understand it. Paul begins to address the nature of communion in 1 Corinthians 10, but continues on in the section numbered as 1 Corinthians 11. Blue comments are mine.
1 Corinthians 11:27-30
Douay-Rheims 1899 American Edition (DRA)
27 Therefore whosoever shall eat this bread, or drink the chalice of the Lord unworthily, shall be guilty of the body and of the blood of the Lord.
28 But let a man prove himself: (examine his conscience) and so let him eat of that bread, and drink of the chalice.
29 For he that eateth and drinketh unworthily, eateth and drinketh judgment to himself, not discerning the body of the Lord.
30 Therefore are there many infirm and weak among you, and many sleep (have died).
In essence, you sin against the Body of Christ, and will be held liable for that, unless you are absolved of that sin. Far better to avoid it in the first place.