“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.” (1 Corinthians 11:27)
How could you be so judgmental?! You can’t withhold Holy Communion from people. You’re keeping salvation from them.
These are the words of modernists in the Church who fail to understand why the Church teaches some people cannot worthily receive Holy Communion. It goes back to ancient times too.
“And this food is called among us Εὐχαριστία [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined.”
~Saint Justin Martyr (First Apology 66:1)
What does Saint Justin mean here? Only those who “believes that the things which we teach are true”: so, only Catholics who believe in Church doctrine from the Sacraments, to life, to even sexuality. Then only those who have “been washed with the washing that is for the remission of sins”: that is those baptized in the Catholic Church. Then those “so living as Christ has enjoined.” What does that mean? It means, “Be perfect even as your heavenly Father is perfect” (Matthew 5:48), which means no adultery, fornication, sodomy, promiscuity, murder, theft, envy, lying, blasphemy or pride for example (rf. Mark 7:21-23).
Going back to Saint Paul’s exhortation this explains why he said those who eat and drink unworthily the Body and Blood of Christ will have to answer to Him on the last day and will be held accountable and therefore guilty. To commit mortal sin and receive Christ’s Flesh and Blood in a conscious state of mortal sin is like hitting somebody, then begging for $100. For this reason Saint John Mary Vianney stated that anybody who “communicates unworthily crucifies Jesus Christ in his heart” (cf. Sermon of Unworthy Communion, tome IV).
This means Protestants, Muslims, Jews, Atheists, Mormons and Buddhists for example cannot receive Holy Communion since they were either never baptized in the Church or have left the Church and are thus no longer in full communion. In addition, abortion doctors, prostitutes, sorcerers and such are also not permitted to receive Holy Communion since they live lifestyles gravely in contrast to Church teaching, hence living in sin.
The idea of receiving Holy Communion is becoming one in communion or fellowship with those whom you share the Flesh and Blood of Christ. You cannot become one in communion with those you’re not in full communion with. Saint Paul says in receiving Holy Communion we become one body in Christ (rf. 1 Corinthians 10:17); you fracture the body of Christ by receiving Holy Eucharist with those you’re not in communion with. From a secular perspective, receiving the Blessed Sacrament when not in full communion with others is like attending a social club and getting all the benefits without being a contributing member. That’s mooching.
Non-Catholics who wish to receive Eucharist must first receive the Sacraments (e.g. Confession and Confirmation, even Baptism [if there was no prior Baptism or if a Baptism was doubtful]). Catholics who are in mortal sin and wish to receive the Sacrament must first go to Confession, making a perfect act of contrition and firm purpose of amendment.