By Sam McDonald
There is ample evidence from Scripture that the Holy Spirit is God:
Acts 5:3-4
Then Peter said, "Ananias, how is it that Satan has so filled your heart that you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land? Didn't it belong to you before it was sold? And after it was sold, wasn't the money at your disposal? What made you think of doing such a thing? You have not lied to men but to God."
Here, the Apostle Peter equates lying to the Holy Spirit with lying to God. Hence, the Holy Spirit is God.
2 Corinthians 3:17-18
17Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom. 18And we, who with unveiled faces all reflect the Lord's glory, are being transformed into his likeness with ever-increasing glory, which comes from the Lord, who is the Spirit.
Here, the Holy Spirit is called the Lord. Another way we can know that the Holy Spirit is God is because the New Testament identifies him as Yahweh from the Old Testament.
Exodus 17:7
And he called the place Massah and Meribah because the Israelites quarreled and because they tested the LORD saying, "Is the LORD among us or not?"
Combined WITH
Hebrews 3:7-9
So, as the Holy Spirit says: "Today, if you hear his voice, do not harden your hearts as you did in the rebellion, during the time of testing in the desert, where your fathers tested and tried me and for forty years saw what I did.
Isaiah 6:8-9
Then I heard the voice of the Lord saying, "Whom shall I send? And who will go for us?" And I said, "Here am I. Send me!" He said, "Go and tell this people: " 'Be ever hearing, but never understanding; be ever seeing, but never perceiving.'
Combined WITH
Acts 28:25-26
25They disagreed among themselves and began to leave after Paul had made this final statement: "The Holy Spirit spoke the truth to your forefathers when he said through Isaiah the prophet: 26" 'Go to this people and say, "You will be ever hearing but never understanding; you will be ever seeing but never perceiving."

