The Christian Church lives by the Holy Spirit. The Spirit alone is the guarantee of God’s Kingdom on earth. He is the sole guarantee that God’s life and truth and love are with men. Only by the Holy Spirit can man and the world fulfill that for which they were created by God. All of God’s actions toward man and the world—in creation, salvation and final glorification—are from the Father through the Son (Word) in the Holy Spirit; and all of man’s capabilities of response to God are in the same Spirit, through the same Son to the same Father.
Thomas Hopko
From the Series: The Orthodox Church
Volume I – Doctrine and Scripture: The Symbol of Faith