How to Explain to a Non-Orthodox Why They Can't Receive Holy Communion.

To communicate to a non-Orthodox Christian that they cannot participate in Holy Communion, you might say something like the following:

“I appreciate your desire to participate in Communion with us. In our tradition, the Eucharist is a sacrament that assumes full agreement in the Orthodox faith, as well as participation in the sacraments of initiation and reconciliation. Because of this, we respectfully restrict Communion to Orthodox Christians who are properly prepared. We don’t do this to exclude, but to uphold the deep significance and sacredness of the Eucharist in our tradition. We warmly welcome you to join us in worship and fellowship, and I’m happy to answer any questions you have about our faith.”

The Orthodox tradition, going back to Apostolic times, restricts participation in the sacrament of Holy Communion to those who have been Baptized and Chrismated in the Orthodox Church and have properly prepared themselves to participate. This is not done out of exclusivity or judgment, but rather it’s a reflection of the sacrament’s deep meaning in Orthodox faith.

The Holy Communion is not simply a memorial of Christ’s sacrifice or a statement of fellowship among believers. It is not a symbolic act. Instead, it’s the actual partaking in the Body and Blood of Christ. This presupposes full unity in faith that is formally expressed through the sacraments of initiation (baptism and chrismation) and maintained through regular Confession and Communion.

St. Paul in his letter to the Corinthians warns Christians of damantion if they partake Holy Communion unworthily: "For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord's body" ( 1Co 11:29). The earliest Christians deemed it better to prevent outsiders from taking communion than to risk them taking communion "unworthily."

Orthodox Christians must be properly prepared to receive Communion. Here are the basic guidelines:  

1. Fasting: Orthodox Christians are required to fast before receiving Communion. The usual rule is to abstain from all food and drink from midnight until receiving Communion the following morning. Some exceptions may be made for those with health conditions or other serious needs. It also expected that the faithful will be participating in the regular Wednesday and Friday fast as well as the special fasting periods.

2. Prayer and Reflection: Prior to receiving Communion, Orthodox Christians are encouraged to spend time in prayer and self-reflection. This includes examining one’s conscience and asking God for forgiveness of any sins to ensure they are in a worthy state to receive Communion. Also, an Orthodox Christian is expected to have a regular daily prayer routine with guidance from a spiritual father. In addition to these, some Orthodox Christians also engage in a practice called “preparation prayers,” a set of prayers specifically designed to prepare one’s heart and mind to receive Communion. 

3. Confession: Regular participation in the sacrament of Confession to a priest is a standard practice in Orthodox Christianity. While it’s not usually required before each Communion, frequent confession is encouraged to maintain spiritual health. When you enter the church you must have a clean conscience.

4. Living a Christian Life: Preparation for Communion isn’t just about the hours before the sacrament; it’s a way of life. Orthodox Christians are called to live in accordance with all the teachings of Christ and His Church, practicing humility, love, forgiveness, and charity.

5. Understanding and Acceptance of Orthodox Doctrine: To receive Communion, one must be an Orthodox Christian in good standing, which includes being baptized and chrismated in the Church, understanding the doctrine of the Apostolic Church as preserved in the Orthodox Church,  and accepting its teachings.

The specifics of preparation can vary based on local custom and personal spiritual direction, so it’s always best for Orthodox Christians to discuss these matters with their priest or spiritual father.