Back to Basics: Receiving Holy Communion

When believers receive Holy Communion, they're intimately united with their Lord and Savior, Jesus Christ. However, Communion isn't limited to the communicant (the one receiving Holy Communion) and Jesus Christ. By taking Holy Communion, the Catholic is also expressing union with all Catholics around the world and at all times who believe the same doctrines, obey the same laws, and follow the same leaders. This is why Catholics (and Eastern Orthodox Christians) have a strict law that only people who are in communion with the Church can receive Holy Communion. In other words, only those who are united in the same beliefs — the seven sacraments, the authority of the pope, and the teachings in the Catechism of the Catholic Church — are allowed to receive Holy Communion.

In Protestant tradition, Communion is often seen as a means of building unity among various denominations, and many have open Communion, meaning that any baptized Christian can take Communion in their services. Catholics and Eastern Orthodox Christians, on the other hand, see communion not as the means but as the final fruit of unity. So only those in communion can receive Holy Communion. It has nothing to do with who's worthy...

Similarly, Catholics who don't follow the Church's laws on divorce and remarriage, or who obstinately reject Church teaching, such as the inherent evil of abortions shouldn't go to Communion, because they're no longer in communion. It's not a judgment on their moral or spiritual state, because only God can know that. But receiving Holy Communion is a public act, and therefore, it's an ecclesiastical action requiring those who do it to be united with all that the Church teaches and commands and with all the ways that the Church prays.

Catholicism for Dummies by John Trigilio