The Holy Things are for the Holy Ones!
One is holy, one is Lord: Jesus Christ to the glory of God the Father. Amen. (from the Divine Liturgy)
And Jesus said to him, “Why do you call me good? No one is good but God alone. (Mark 10:18)
St. Nicholas Cavasilas commenting on the Divine Liturgy says:
On the point of approaching the Holy Table…partaking of the Mystery is not permitted to all …
The holy [Mysteries] are for the holy!
… The faithful are called holy because of the Holy Mysteries of which they partake, because of him whose Body and Blood they receive.
Members of His Body – flesh of his flesh and bone of his bone – as long as we remain united to him and preserve our connection with him [i.e., live in communion with the altar – Ed.], we live by holiness, drawing to ourselves through the Holy Mysteries, the sanctity which comes from that Head and that Heart. But if we should cut ourselves off, if we should separate ourselves from the unity of this most holy Body, we would partake of the Holy Mysteries in vain, for life cannot flow into dead and amputated limbs. And what can cut off the members form this holy Body? It is your sins which have separated me from you, [Is. 59.2], says God. Does all sin then bring death to man? No, indeed, but deadly sin only; that is why it is called deadly. For according to St. John [1 Jn. 5.16,17] there are sins which are not deadly.
That is why Christians, if they have not committed such sins as would cut them off from Christ and and bring death, are in no way prevented from partaking of the Holy Mysteries and receiving sanctification… (quoted in The Divine Liturgy of the Great Church, p. 107)
For St. Nicholas Cabasilas the words in the Liturgy – Holy things are for the holy! – is packed with meaning. The “holy things” refer to the Holy Mysteries such as Holy Communion. These Mysteries are given not for everyone, but to the Holy Ones of God, the saints. In the Liturgy they are given to the Faithful. The people of the parish are (and are to be!) the Holy Ones of God. For him, it is obvious why there is a practice of “closed” Communion. One has to desire to be among the faithful, among the Holy Ones to receive the Holy Mysteries. They are gifts for those who seek the Lord – for those who choose and desire to live a holy life. Holiness is not magic that can change someone into something they are not. Holiness comes to those who choose to be united to the Holy One of God, Jesus Christ. We maintain holiness by maintaining our unity with Christ whose Body is the Church.
Fr Alexander Schmemann in For the Life of the World leads us into the mystery:
“Holy” is the real name of God, of the God “not of scholars and philosophers,” but of the living God of faith. The knowledge about God results in definitions and distinctions. The knowledge of God leads to this one, incomprehensible, yet obvious and inescapable word: holy. And in this word we express both that God is the Absolutely Other, the One about whom we know nothing, and that He is the end of all our hunger, all our desires, the inaccessible One who mobilizes our wills, the mysterious treasure that attracts us, and there is really nothing to know but Him. “Holy” is the word, the song, the “reaction” of the Church as it enters into heaven, as it stands before the heavenly glory of God. (Kindle Location 389-395)
For Fr Schmemann holiness is the goal of our spiritual sojourn. When we receive the Holy Mysteries of God and become the Holy Ones of God, we have come to the very purpose of our existence. In the Holy Mysteries we are united to the One who is Holy, Jesus Christ.