Our Church believes that the Holy Spirit is God. He is the third Person of the Holy Trinity. He is equal to the other two Persons of the Holy Trinity, the Father and the Son. This belief of our Church is based on both the Holy Scriptures and on Holy Tradition.
In the Old Testament it is mentioned that the Prophet Isaiah talked with the Holy Spirit (Isaiah, 6:1-10). This is confirmed when St. Paul says, "Well spoke the Holy Spirit by Isaiah the Prophet to our Fathers" (Acts, 28:25). A similar passage is found in the Prophet Jeremiah. And again we have the witness of St. Paul, who confirms that "the Holy Spirit" speaks (Hebrews, 10:15-17). There are many more similar passages in the Old Testament that bear witness that the Holy Spirit is God.
In the New Testament many passages bear witness. When Christ was resurrected, He said to His Disciples, "Go you and teach all nations, baptizing them in the Name of the Father, and the Son, and the Holy Spirit" (Mark, 16:15). Here the Holy Spirit is equal to the Father and to the Son. There is no doubt that He is God. Saint Peter categorically calls the Holy Spirit, "God" (Acts, 5:4). And St. Paul characteristically says, "Now the Lord is that Spirit" (II Corinthians, 3:17). In very many other places in the New Testament the Divinity of the Holy Spirit is revealed. It is not necessary, however, to mention them all here.
In opposing the heresy of Macedonios against the Holy Spirit, the Second Ecumenical Council, which took place at Constantinople in the year 381 A.D., produced the eighth article of the Creed, which states, ". . . and [I believe] in the Holy Spirit, the Lord, the Giver of Life, Who proceeds from the Father, and is worshipped and glorified together with the Father and the Son, Who spoke through the Prophets." This is a teaching that is absolutely based on the Holy Scriptures and Holy Tradition. Pay attention to these words: "worshipped and glorified together with the Father and the Son." Who is worshipped and glorified? God. God alone. And so, since the Holy Spirit is worshipped and glorified together with the Father and the Son, He is also True God.
Many opposed this Orthodox belief. In the Fourth Century, it was Macedonios and his followers. They said that the Holy Spirit is not uncreated God, as is the Father and the Son. They said that He is a creation, and therefore no different from all other created beings; no created being is God, and so the Holy Spirit cannot be God. This arbitrary opinion cannot be supported by Holy Scripture or Holy Tradition.
In our times there are others who are worse than the followers of Macedonios. The Jehovah's Witnesses deny the existence of the Holy Spirit. The worst is that they call themselves students of the Holy Scriptures. Even a brief glimpse at the Holy Scriptures would show them not only the existence of the Holy Spirit but also His Divinity.
With the use of the word spirit, The Holy Scriptures frequently refer to the other two Persons of the Holy Trinity, the Father and the Son. Why? As Theodoritos the Compiler says, "To show us that the divine nature of the Three Persons is one and the same, spiritual and immaterial, unembodied and indescribable." And he adds, "Nevertheless, the Spirit is Holy, and only the Third Person is called the Holy Spirit."
There is much to be said in interpreting the many passages of the Holy Scriptures that refer to the Holy Spirit. However, it is not our intention to interpret all of these passages here. But we do find it necessary to look at a particular passage that is often misunderstood. St. Mark writes, "All sins shall be forgiven unto the sons of men, and blasphemies wherewithsoever they shall blaspheme. But he that shall blaspheme against the Holy Spirit has never forgiveness but is in danger of eternal damnation" (Mark, 3:28-29). Blasphemy against the Holy Spirit is an unforgivable sin. The problem is that this passage seems to forgive blasphemy against the Son but not against the Holy Spirit. The passage can be very easily misunderstood to mean that the Holy Spirit is superior to the Son. The correct interpretation, as it is given to us by the Church Fathers, is this: blasphemy against the Holy Spirit is the denial by man out of hatred of God's power to save him. Even more simply, the man who does not believe that the grace of God--the Father, the Son, and the Holy Spirit--can save him, closes his heart to the actions of the Holy Spirit; he does not accept Grace. He does not proceed to repentance. He fights against the sanctifying and saving act of God. He creates within himself a sorrowful and incurable condition.
"Heavenly King and Comforter, the Spirit of Truth, Who are everywhere and fill all things, come and abide in us and cleanse us from every stain and save, O Good One, our souls." Relieve every man of sorrowful incurable non-repentance and the denial of Your sanctifying and saving action. Make us aware of our shortcomings and sins. Grant us faith in the Trinitarian God, sincere repentance, a returning to You. Grant us the salvation of our Souls and that of all the world.