1 Corinthians 11:28-31

28Everyone ought to examine themselves before they eat of the bread and drink from the cup. 29For those who eat and drink without discerning the body of Christ eat and drink judgment on themselves. 30That is why many among you are weak and sick, and a number of you have fallen asleep. 31But if we were more discerning with regard to ourselves, we would not come under such judgment.