These words, variously translated as “The Existing One” or “He Who Is,” are in essence the name that God gave himself when Moses came before him asking (in Exodus 3:13-15), “If I come to the people of Israel and say to them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’ what shall I say to them?” God said to Moses, “I AM WHO I AM”. And He said, “Thus you shall say to the children of Israel, ‘I AM has sent me to you.’ ” Moreover God said to Moses, “Thus you shall say to the children of Israel: ‘The LORD, the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has sent me to you. This is My name forever, and thus I am to be remembered throughout all generations . . .’ The word in capital letters, LORD, represents the Hebrew letters YHWH, associated with the verb “to be.” These four letters (or “Tetragrammaton”) were to the Jews the unpronounceable name of God.
That God gave this as his name reflects that truth that, while the gods of the nations had various names, God is nameless, beyond all name and concept—his various “names” and titles being mere pointers to the nature of him whose essence is beyond all. This name is a kind of negation of name, underscoring the mystery and namelessness of God. Indeed, it confirms what the Church fathers later taught, that God so surpasses all that can be imagined about Him that the “negative [or apophatic] way” of speaking of him is superior to the positive (cataphatic) way of his many titles.
This same name was also chosen by Jesus in the Gospel, when he said, “. . . before Abraham was, I AM” (John 8:58) and also in his many “I am” declarations (“I am the light of the world”, “I am the true vine”, etc.). In the Greek text of the Gospel these “I am” sayings take the form “ego eimi,” denoting emphasis. By using this name, Jesus identified himself with the God who had spoken to Moses and in doing so had given himself that same name; he was the God who had led Israel out of bondage to Egypt.
Appropriately, this name, by which God the Word identified himself to his people in both the Old and New Testaments, is the name used on the holy icons of Christ to identify the Savior: the Greek letters “O WN” have the meaning “He who Is” or “The existing one”, and these same words are again used in the concluding parts of the services of vespers and matins (orthros), to remind us that Jesus Christ is “YHWH [He Who Is], the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob.”
There are two blessings at the end of the service. The first one blesses (speaks well of) God, and the second blesses God’s people (asks for God’s blessing on them). Praise of God precedes petition. The first blessing is based on the name God gave himself: “Christ our God, the Existing [He who Is] is blessed, always, now and ever, and unto ages of ages.” The second blessing concludes the service “May Christ our true God . . . have mercy on us and save us . . .”