The Holy Spirit is a person amongst us just as Jesus and the Father are. Wikipedia says that, "a person is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility." The defining features of personhood and consequently what makes a person count as a person differ widely among cultures and contexts. Somebody that performs these personal things in relationship — like God, angels, and human beings — is a person.
Furthermore, every pronoun used in reference to the Spirit, even though the Greek is the neuter word "pneuma" is normally "he" and occasionally "she" but not "it." For example Jesus says in John 15.26, "When the Advocate comes, whom I will send to you from the Father — the Spirit of truth who goes out from the Father — he will testify about me." Also in John 16.13-14 we read, "But when he, the Spirit of truth, comes, he will guide you into all the truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. He will glorify me because it is from me that he will receive what he will make known to you." There is equality in the Godhead and all three members of the Trinity are persons. Just as something flashes in the corner of our eye and we automatically glance over thinking someone is there, so the Holy Spirit person flashes in our lives. We sense his presence even though he is invisible.✞
Lord Donald Coggan (1909-2000) the late Archbishop of Canterbury, who incidentally commissioned me as an evangelist in the Church of England in 1975, wrote in his little book, "The Christian Faith" that "The Holy Spirit has a way of annihilating the barriers of time and distance and making Jesus our great contemporary." The Holy Spirit attributes point to his personality. The Holy Spirit empowers God's people as in Zechariah 4.6, "So he said to me, 'This is the word of the Lord to Zerubbabel: 'Not by might nor by power, but by my Spirit,' says the Lord Almighty." The Holy Spirit is endued with life as in Romans 8.2, "because through Christ Jesus the law of the Spirit who gives life has set you free from the law of sin and death." Note that the singular "you" is translated as "me" in some manuscripts. The Holy Spirit is omniscient or all knowing as in 1 Corinthians 2.10-11, "these are the things God has revealed to us by his Spirit. The Spirit searches all things, even the deep things of God. For who knows a person's thoughts except their own spirit within them? In the same way no one knows the thoughts of God except the Spirit of God."✞
Jesus instructed his disciples about this same truth in John 14.26, "But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you." The person of the Holy Spirit also instructs us the about the mind of God. As it is written, "The Holy Spirit leaks things from the mind of God." In the same vein, we read in Hebrews 9.14, "How much more, then, will the blood of Christ, who through the eternal Spirit offered himself unblemished to God, cleanse our consciences from acts that lead to death, so that we may serve the living God!" "death" may also be translated as "from useless rituals."✞