26] For as often as you shall eat this bread, and drink the chalice, you shall shew the death of the Lord, until he come.  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.  But let a man prove himself: and so let him eat of that bread, and drink of the chalice.  For he that eateth and drinketh unworthily, eateth and drinketh judgment to himself, not discerning the body of the Lord.  Therefore are there many infirm and weak among you, and many sleep
I specifically wonder about (25). What is meant by “drinking of the chalice of The Lord unworthily”? I take it a Catholic answer would be that it means to partake in the Eucharistic sacrament without being initiated into the Church or with mortal sin on ones being etc. What does this passage mean to a Protestant, who knows his theology?