Jehovah's Witnesses deny that Christ is God. When they go door-knocking they're usually well-coached on how to discuss their views on this matter. That's why, when they knock on my door, I talk about something they're less prepared to discuss -- the Personhood of the Holy Spirit.
You see, they also deny that the Holy Spirit is God. In fact, they deny that he is even a Person, claiming instead that he is "God's active force by which he accomplishes his purpose and executes his will" (Insight on the Scriptures, 2:1019). Official WatchTower publications even compare the Holy Spirit to impersonal forces such as radio waves (ibid., 2:1020).
But for someone who makes an unbiased reading of the Scriptures, references to the Holy Spirit's Personhood leap off the page. For example, Paul speaks of it being possible to grieve the Holy Spirit: "And do not grieve the Holy Spirit of God, in whom you were sealed for the day of redemption" (Eph. 4:30). Of course, it is not possible to offend or displease impersonal forces.
Paul speaks of the Holy Spirit as knowing the thoughts of God-indicating that the Spirit has an intellect: "For what person knows a man's thoughts except the spirit of the man which is in him? So also no one comprehends the thoughts of God except the Spirit of God" (1 Cor. 2:11).
He also speaks of the Holy Spirit exercising the faculty of will, as in the distribution of spiritual gifts: "All these are inspired by one and the same Spirit, who apportions to each one individually as he wills" (1 Cor. 12:11).
Scripture also teaches that the Holy Spirit serves as a Paraclete (Greek parakletos) on our behalf. This term, often translated as "Comforter," "Counselor," "Advocate," or "Helper," refers to a person who is called or summoned to aid one, especially in legal settings, where he serves as an advisor, or advocate for the accused.
Jesus repeatedly speaks of the Holy Spirit as a Paraclete whom he will send to help us: "The Advocate [parakletos], the Holy Spirit that the Father will send in my name-he will teach you everything and remind you of all that I told you" (John 14:26; cf. 15:26, 16:7-8).
A facet of the Greek text not obvious in translation is that in the three verses just mentioned (and others), Jesus applies the masculine pronoun ekeinos to the Holy Spirit. The personal character of a paraclete is further illustrated by the fact that Jesus also serves as our Paraclete before the Father: "My little children, I am writing this to you so that you may not sin; but if any one does sin, we have an Advocate [parakletos] with the Father, Jesus Christ the righteous" (1 John 2:1)
There are also many passages in Scripture that refer to the Holy Spirit communicating with us-again, something an impersonal force cannot do. For example, when testifying before the Sanhedrin, the apostles refer to the Holy Spirit as their co-witness: "And we are witnesses to these things, and so is the Holy Spirit whom God has given to those who obey him" (Acts 5:32). Later in Acts, Paul states that the Holy Spirit testifies: "The Holy Spirit testifies to me in every city that imprisonment and afflictions await me" (Acts 20:23).
This testimony sometimes came from the mouths of New Testament prophets who attributed the words directly to the Holy Spirit: "And coming to us he took Paul's girdle and bound his own feet and hands, and said, 'Thus says the Holy Spirit, "So shall the Jews at Jerusalem bind the man who owns this girdle and deliver him into the hands of the Gentiles"'" (Acts 21:11; cf. 1 Tim. 4:1). Note the formula "Thus says the Holy Spirit" is modeled on the frequent prophetic formula "Thus says the Lord"-indicating not only the Spirit's Personhood but also directly equating him with Yahweh.
Sometimes even the biblical books' narrative directly quotes the Holy Spirit. In Revelation we read, "And I heard a voice from heaven saying, 'Write this: Blessed are the dead who die in the Lord henceforth.' 'Blessed indeed,' says the Spirit, 'that they may rest from their labors, for their deeds follow them!'" (Rev. 14:13).
If it were objected that this quotation is found in a book of prophecy, which often uses figurative language, the topper is Acts 13:2:"While they were worshiping the Lord and fasting, the Holy Spirit said, 'Set apart for me Barnabas and Saul for the work to which I have called them.'"
The doctrinal force of this passage is unavoidable. Here we have a direct quotation of the Holy Spirit-not in a prophetic book, not in the mouth of a prophet, not in a parable, not told by a character in a historical book. We have the Holy Spirit directly quoted by the narrative of a historical book-just like the other real persons who speak in the book. And the same thing happens in Acts 8:29 and 10:19.
Even if one tried to explain away all of Scripture's other personal references to the Holy Spirit as somehow being symbols or figures of speech, the direct quotation of an individual in the narrative of a historical book unmistakably shows that the individual in question is a real, literal person, not just a force or symbol.