The Holy Spirit is not an impersonal force: He is a Person, fully God, whom Jesus promised to send to dwell in His people, teach them, and bear witness to Him. The entire New Testament assumes that He is present and active in every believer.
Not a summary of these passages: the passages themselves. Read them, then come back to the study below.
The study
What the Scripture says
1
The Spirit is a Person, not a force
Scripture speaks of the Spirit as someone who speaks, teaches, testifies, guides, and can be grieved. He is not an 'it': Jesus calls Him 'the Helper' and uses personal pronouns. A force cannot be lied to; a Person can. This is why the Spirit is Someone to know, not something to use.
But the Counselor, the Holy Spirit, whom the Father will send in my name, he will teach you all things, and will remind you of all that I said to you.
However when he, the Spirit of truth, has come, he will guide you into all truth, for he will not speak from himself; but whatever he hears, he will speak. He will declare to you things that are coming.
In the upper room, Jesus promised that the Father would send the Spirit of truth to dwell with His people: 'another' Helper, of the same kind as Jesus Himself. He even said it was to our advantage that He go away, because the Helper would come. The Spirit is the presence of Jesus with us now.
I will pray to the Father, and he will give you another Counselor, that he may be with you forever,— the Spirit of truth, whom the world can’t receive; for it doesn’t see him, neither knows him. You know him, for he lives with you, and will be in you.
Nevertheless I tell you the truth: It is to your advantage that I go away, for if I don’t go away, the Counselor won’t come to you. But if I go, I will send him to you.
The Spirit does not draw attention to Himself. He takes what belongs to Christ and declares it to us, and He bears witness to Jesus. Whenever the Spirit genuinely works, Jesus becomes more real and more glorious, never less.
However when he, the Spirit of truth, has come, he will guide you into all truth, for he will not speak from himself; but whatever he hears, he will speak. He will declare to you things that are coming. He will glorify me, for he will take from what is mine, and will declare it to you.
Paul writes that anyone who does not have the Spirit of Christ does not belong to Christ, and that our bodies are temples of the Holy Spirit. The Spirit is the seal and the deposit: God's guarantee that we belong to Him and that the inheritance is coming.
But you are not in the flesh but in the Spirit, if it is so that the Spirit of God dwells in you. But if any man doesn’t have the Spirit of Christ, he is not his.
in whom you also, having heard the word of the truth, the Good News of your salvation—in whom, having also believed, you were sealed with the Holy Spirit of promise, who is a pledge of our inheritance, to the redemption of God’s own possession, to the praise of his glory.
The Spirit produces His fruit in our character: love, joy, peace, patience, kindness, goodness, faith, gentleness, self-control. He gives gifts for serving others, and when we don't know how to pray, He Himself intercedes for us with groanings too deep for words.
But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faith, gentleness, and self-control. Against such things there is no law.
Now there are various kinds of gifts, but the same Spirit. There are various kinds of service, and the same Lord. There are various kinds of workings, but the same God, who works all things in all. But to each one is given the manifestation of the Spirit for the profit of all. For to one is given through the Spirit the word of wisdom, and to another the word of knowledge, according to the same Spirit; to another faith, by the same Spirit; and to another gifts of healings, by the same Spirit; and to another workings of miracles; and to another prophecy; and to another discerning of spirits; to another different kinds of languages; and to another the interpretation of languages. But the one and the same Spirit works all of these, distributing to each one separately as he desires.
In the same way, the Spirit also helps our weaknesses, for we don’t know how to pray as we ought. But the Spirit himself makes intercession for us with groanings which can’t be uttered. He who searches the hearts knows what is on the Spirit’s mind, because he makes intercession for the saints according to God.
I will pray to the Father, and he will give you another Counselor, that he may be with you forever,— the Spirit of truth, whom the world can’t receive; for it doesn’t see him, neither knows him. You know him, for he lives with you, and will be in you.
However when he, the Spirit of truth, has come, he will guide you into all truth, for he will not speak from himself; but whatever he hears, he will speak. He will declare to you things that are coming. He will glorify me, for he will take from what is mine, and will declare it to you.
But you are not in the flesh but in the Spirit, if it is so that the Spirit of God dwells in you. But if any man doesn’t have the Spirit of Christ, he is not his.
But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faith, gentleness, and self-control. Against such things there is no law.