Throughout the Bible it is clear that the Holy Spirit is God Himself. This is seen in the attributes which are given to the Holy Spirit in Scripture, for example. Without exception these attributes are those of God Himself.
He is eternal: This means that there never was a time when He was not. “How much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God?” (Hebrews 9:14).
He is all-powerful: “And the angel answered and said to her, ‘The Holy Spirit will come upon you, and the power of the Most High will overshadow you; and for that reason the holy offspring shall be called the Son of God’” (Luke 1:35).
He is everywhere present (that is, omnipresent) at the same time: “Where can I go from Thy Spirit? Or where can I flee from Thy presence?” (Psalm 139:7).
He is all-knowing (that is, omniscient): “For to us God revealed them through the Spirit; for the Spirit searches all things, even the depths of God. For who among men knows the thoughts of a man except the spirit of the man, which is in him? Even so the thoughts of God no one knows except the Spirit of God” (1 Corinthians 2:10, 11).
The Holy Spirit is called God: “But Peter said, ‘Ananias, why has Satan filled your heart to lie to the Holy Spirit, and to keep back some of the price of land? While it remained unsold, did it not remain your own? And after it was sold, was it not under your control? Why is it that you have conceived this deed in your heart? You have not lied to men, but to God’” (Acts 5:3, 4, italics mine).
“And we all, with unveiled face, beholding the glory of the Lord, are being changed into his likeness from one degree of glory to another; for this comes from the Lord who is the Spirit” (2 Corinthians 3:18 RSV).
He is the Creator: The first biblical reference to the Holy Spirit is Genesis 1:2 (Moffatt) where we are told “the spirit of God was hovering over the waters.” Yet Genesis 1:1 says, “In the beginning God created the heavens and the earth.” And in Colossians 1 where Paul is writing to the Church at Colossae about the Lord Jesus Christ, among other tremendous truths he tells us, “For in Him all things were created, both in the heavens and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things have been created through Him and for Him. And He is before all things, and in Him all things hold together” [cohere] (Colossians 1:16, 17).
Thus, God the Father, God the Son, and God the Holy Spirit were together creating the world. To understand and accept these facts is of the greatest importance to every Christian, both theologically and practically.
One day I made a few of these assertions about the Holy Spirit to some seminary students. One asked, “But He is usually mentioned last. Doesn’t that imply inferiority?” Yet in Romans 15:30 He is not mentioned last: “Now I urge you, brethren, by our Lord Jesus Christ and by the love of the Spirit, to strive together with me in your prayers to God for me.” And in Ephesians 4:4 Paul says, “There is one body and one Spirit, just as also you were called in one hope of your calling.”
But more than this, the usual placement of the three persons of the Trinity in the New Testament has to do with their order and function. Thus we say that we pray to the Father through the Son and in the power of the Holy Spirit. Moreover, I have already shown that functionally the Father came first, then the Son became incarnate, died and rose again. Now the Spirit does His work in this age of the Spirit. The order has nothing to do with equality, but only with function and chronology.
from The Holy Spirit by Billy Graham