The Jehovah's Witnesses believe: "The holy spirit is not a person; it is God's active force."1
Since they do not believe that the Holy Spirit is either a person, or God, but just a force, they do not write "Holy Spirit" with capital letters, even when translating Scripture. Other translators consider Him God, and capitalize. This has become proper English usage, as a glance at a dictionary will show.
After reading the passages that touch on this, I believe you will agree that the Holy Spirit stands out both as a divine person, and as God. Lets notice first that His actions are not just those of a force, but that He does things that only a person can do. After that we will examine His divinity.
The Holy Spirit Is a Person, Not Just a Force
He Does All the Things That Distinguish a Person from a Force
A force pushes or pulls or otherwise exerts pressure. People can exert force, but so can water, wind and gravity. People have many other abilities that forces don't have. The following are some of them. Other than the titles, I give almost no comment. May the Scriptures themselves speak to your heart as you interpret them for yourself.
Forces Don't Know and Teach, The Spirit Does
"But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God. For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God. Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God. Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth…" (1 Cor. 2:11-12).
"For the Holy Ghost shall teach you in the same hour what ye ought to say" (Luke 12:12, See also 1 Cor. 2:10, 13; John 14:26).
The Spirit Has Emotions, Forces Don't
He loves: "Now I beseech you, brethren, for the Lord Jesus Christ's sake, and for the love of the Spirit…" (Rom. 15:30).
He can be grieved: "And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption" (Eph. 4:30).
He can be insulted: "…and hath done despite unto the Spirit of grace" (Heb. 10:29).
The Spirit Speaks
"He that hath an ear, let him hear what the Spirit saith unto the churches…" (Rev. 2:7, See also: Rev. 2:11,17; 3:6, 13, 22; Acts 1:16; 8:29; 10:19; 11:12; 2 Pet. 1:21).
He speaks in the first person: "…Well spake the Holy Ghost by Esaias the prophet unto our fathers saying… and I should heal them" (Acts 28:25-27).
Can a force speak of the future?: "…which the Holy Ghost by the mouth of David spake before concerning Judas…" (Acts 1:16, See also 20:23, John 16:13-14).
He testifies: "But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of truth, which proceedeth from the Father, he shall testify of me" (John 15:26).
The Spirit Gave the Ability to Speak in Foreign Languages
"And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance" (Acts 2:4).
The Spirit Guides
"Howbeit when he, the Spirit of truth, is come, he will guide you into all truth…" (John 16:13).
"For as many as are led by the Spirit of God, they are the sons of God" (Rom. 8:14).
The Spirit Ordains
He sends out missionaries: "…the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them. So they, being sent forth by the Holy Ghost, departed unto Seleucia" (Acts 13:2 - 4).
He appoints overseers: "…Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God…" (Acts 20:28).
What Else Might a Person Do?
He comforts: "But the Comforter, which is the Holy Ghost…" (John 14:26; see also 14:16-17; 15:26).
He helps: "Likewise the Spirit also helpeth our infirmities" (Rom. 8:26).
He investigates: "…the Spirit searcheth all things…" (1 Cor. 2:10).
He reveals: "But God hath revealed them unto us by his Spirit…" (1 Cor. 2:10).
He intercedes: "…the Spirit itself maketh intercession for us…" (Rom. 8:26).
He can be blasphemed: "…the blasphemy against the Holy Ghost shall not be forgiven…" (Matt. 12:31).
It's possible to lie to him: "Ananias, why hath Satan filled thine heart to lie to the Holy Ghost…" (Acts 5:3).
Arguments to the Contrary
Someone might answer, "It's true that the Spirit has all of the characteristics of a person, but He is still not a person because He has no body."
Remember, God the Father has no body either. If the lack of a body reduces the Holy Spirit to a force without a personality, what does it do to the Father?
The Holy Spirit is God
His Divinity is Stated
"Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty" (2 Cor. 3:17). Notice who the Spirit is according to the New World Translation: "Now Jehovah is the Spirit; and where the spirit of Jehovah is, there is freedom."
"…exactly as done by Jehovah the Spirit" (2 Cor. 3:18, New World Translation).
His Divinity Is Demonstrated
The same Holy Spirit is called the Spirit of Jehovah, the Spirit of God, and the Spirit of Christ. What is done to God's Spirit is done to God Himself:
"…Ananias, why hath Satan filled thine heart to lie to the Holy Ghost… thou hast not lied unto men, but unto God" (Acts 5:3-4).
"Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?" (1 Cor. 3:16).
"And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father" (Gal. 4:6. See also Rom 8:9; 1 Pet. 1:11).
The Spirit of God Is the Spirit of Christ, and Only Those in Whom He Dwells Are Saved
"But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his… But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you" (Rom. 8:9,11).