Q. 104: What is required to the worthy receiving of the Lord’s Supper?
A. It is required of them that would worthily partake of the Lord’s Supper, that they examine themselves of their knowledge to discern the Lord’s body, of their faith to feed upon Him, of their repentance, love, and new obedience, lest coming unworthily they eat and drink judgment to themselves.
But let a man examine himself, and so let him eat of the bread and drink of the cup. For he who eats and drinks in an unworthy manner eats and drinks judgment to himself, not discerning the Lord’s body. 1 Corinthians 11:28-29