Is the Holy Spirit God?
Yes, the Holy Spirit is God. The Nicene-Constantinople Creed says the Holy Spirit “proceeds from the Father and the Son, who with the Father and the Son is adored and glorified.”
Jesus testifies that the Holy Spirit is a person in John 14 when he calls the Holy Spirit the paraclete, a Greek word that can be translated as “advocate,” “defense attorney,” “spokesman,” “mediator,” “intercessor,” “comforter,” or “consoler”—all personal terms.
In the epistle to the Hebrews, St. Paul quotes the Holy Spirit speaking in the first person as God:
Therefore, as the Holy Spirit says: “Oh, that today you would hear his voice, harden not your hearts as at the rebellion in the day of testing in the desert, where your ancestors tested and tried me and saw my works for forty years. Because of this I was provoked with that generation and I said, “They have always been of erring heart, and they do not know my ways” (Heb. 3:7-10).