Is the Holy Spirit God?
Yes. The Spirit proceeds from the Father and the Son and with the Father and the Son is worshiped and glorified. He has spoken through the prophets.
Catechism for the Global Methodist Church, question 21
19Therefore go and make disciples, baptizing them in the name of the Father and of the Son and of the Holy Spirit. 20Teaching them to keep everything that I have commanded you; and behold, I am with you all the days until the end of the age."
9You, however, are not in the flesh but in the Spirit, provided that the Spirit of God dwells in you. Anyone who does not have the Spirit of Christ does not belong to him.
9But as it is written, No eye has seen, no ear has heard, and no human heart has conceived what God has prepared for those who love him. 10For God has revealed these things to us through the Spirit, for the Spirit searches all things, even the depths of God. 11For who among humans knows the things of a human except the spirit of the human that is in him? In the same way, no one has known the things of God except the Spirit of God.
16Do you not know that you are God's temple and that the Spirit of God dwells in you?
6And because you are sons, God has sent the Spirit of his Son into our hearts, crying, "Abba! Father!"
2The Spirit of the LORD spoke in me, and his speech was upon my tongue.
1The Spirit of the Lord GOD is upon me, because the LORD has anointed me to bear tidings to the poor. He has sent me to bind up the brokenhearted, to proclaim liberty to the captives, and to open release to those who are bound. 2To proclaim the year of the LORD's favor and the day of vengeance of our God, to comfort all who mourn. 3To set for those who mourn in Zion: to give them a headdress instead of ashes, the oil of rejoicing instead of mourning, the mantle of praise instead of a faint spirit; and they will be called terebinths of righteousness, a planting of the LORD, to display splendor.
12And their heart they set as flint from hearing the instruction and the words that the LORD of Hosts sent by his Spirit by the hand of the earlier prophets, and great wrath came from the LORD of Hosts.
22All this happened so that what had been spoken by the Lord through the prophet might be fulfilled. 23Look, the virgin will conceive and give birth to a Son, and they will call his name Immanuel, which is translated "God with us."
1God spoke to the fathers in the prophets little by little and in many ways of old. 2In these last days he has spoken to us in a Son, whom he appointed heir of all things, through whom he also made the ages.
10Concerning this salvation the prophets who prophesied about the grace that was to be yours searched and inquired. 11inquiring what time or circumstances the Spirit of Christ in them was indicating when he predicted the sufferings of Christ and the glories that would follow. 12To whom it was revealed that they were serving not themselves but you, in the things that have now been reported to you through those who preached to you by the Holy Spirit sent from heaven: things into which angels long to look.
20This first, knowing that no prophecy of Scripture comes of one's own explanation. 21For prophecy was never borne by the will of a human, but men spoke from God as they were borne by the Holy Spirit.
The Holy Spirit is God. He "proceeds from the Father and the Son," he "with the Father and the Son is worshiped and glorified," and he "has spoken through the prophets." Article IV of the Articles of Religion says the Holy Ghost is "of one substance, majesty, and glory with the Father and the Son, very and eternal God," and Article III of the Confession of Faith calls him "one in being with the Father and the Son."
In scripture the Spirit stands where only God can stand. Jesus commands baptism "in the name of the Father and of the Son and of the Holy Spirit" (Matthew 28:19), one name shared by three persons. Paul writes that "the Spirit searches all things, even the depths of God," and that "no one has known the things of God except the Spirit of God" (1 Corinthians 2:10-11). Because the Spirit is God, the believer in whom he dwells is "God's temple" (1 Corinthians 3:16). He is the Spirit of the Father and of the Son together. In Romans 8:9 the same Spirit is called "the Spirit of God" and "the Spirit of Christ," and in Galatians 4:6 "God has sent the Spirit of his Son into our hearts, crying, 'Abba! Father!'"
The Spirit who is worshiped with the Father and the Son is the Spirit who gave us the Bible. David testified, "The spirit of the LORD spoke in me, and his speech was upon my tongue" (2 Samuel 23:2). Zechariah calls the message of the prophets the words "the LORD of Hosts sent by his spirit by the hand of the earlier prophets" (Zechariah 7:12). Matthew says the virgin birth fulfilled "what had been spoken by the Lord through the prophet" (Matthew 1:22), and Hebrews says that the God who "spoke to the fathers in the prophets" has now "spoken to us in a Son" (Hebrews 1:1-2). Peter writes that "men spoke from God as they were borne by the holy Spirit" (2 Peter 1:21).
Because the Spirit is God, the church worships him. Methodists sing the Gloria Patri to Father, Son, and Holy Spirit together, baptize in the threefold name, and open the Bible expecting the Spirit who inspired it to illumine it. A believer who prays to the Spirit, thanks him, and obeys him is giving to God what belongs to God, because the Spirit is the Lord who is to be adored.