The Holy Spirit is the third person of the Trinity, fully God, co-equal with the Father and Son, representing God's active presence, power, and personal presence in the world and in believers' lives, acting as a guide, comforter, Paraclete Paraclete (Paráklētos), found in John's Gospel, refers to a divine helper, advocate, or counselor, most commonly identified as the Holy Spirit, whom Jesus promised to send to assist believers after His departure. It means someone called to one's side for encouragement, teaching, and defense, a role Jesus Himself played, and which the Spirit continues as "another Paraclete".  The Holy Spirit is a teacher, a source of spiritual life, gifts, and empowerment for living righteously and witnessing for Christ. He is described with personal attributes (mind, will, emotions) and divine characteristics, omnipresence, omniscience, eternality. The Holy Spirit is called the comforter by Jesus. The Holy Spirit indwells the body of the believer as the spirit of God.

Related Verses.
I Corinthians 6:19-20 
What? know ye not that your body is the Temple of the Holy Ghost 
which is in you and ye are not your own. For ye are bought with a price:
therefore glorify God in your body and in your spirit which are God's.

John 14: 25 These things have I spoken unto you, being yet present with you. 26 But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.

Galatians 5: 22 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, 23 Meekness, temperance: against such there is no law. 24 And they that are Christ's have crucified the flesh with the affections and lusts. 25 If we live in the Spirit, let us also walk in the Spirit.

Acts 1: 8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.

Romans 8: 26 Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered. 27 And he that searcheth the hearts knoweth what is the mind of the Spirit, because he maketh intercession for the saints according to the will of God. 28 And we know that all things work together for good to them that love God, to them who are the called according to his purpose.

Ephesians 4: 30 And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption.

Acts 2: 1 And when the day of Pentecost was fully come, they were all with one accord in one place. 2 And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting. 3 And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. 4 And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance. 5 And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. 6 Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language. 7 And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans? 8 And how hear we every man in our own tongue, wherein we were born? 9 Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia, 10 Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes, 11 Cretes and Arabians, we do hear them speak in our tongues the wonderful works of God. 12 And they were all amazed, and were in doubt, saying one to another, What meaneth this? 13 Others mocking said, These men are full of new wine. 14 But Peter, standing up with the eleven, lifted up his voice, and said unto them, Ye men of Judaea, and all ye that dwell at Jerusalem, be this known unto you, and hearken to my words: 15 For these are not drunken, as ye suppose, seeing it is but the third hour of the day. 16 But this is that which was spoken by the prophet Joel; 17 And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: 18 And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy: 19 And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke: 20 The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come: 21 And it shall come to pass, that whosoever shall call on the name of the Lord shall be saved. 22 Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know: 23 Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken, and by wicked hands have crucified and slain: 24 Whom God hath raised up, having loosed the pains of death: because it was not possible that he should be holden of it. 25 For David speaketh concerning him, I foresaw the Lord always before my face, for he is on my right hand, that I should not be moved: 26 Therefore did my heart rejoice, and my tongue was glad; moreover also my flesh shall rest in hope: 27 Because thou wilt not leave my soul in hell, neither wilt thou suffer thine Holy One to see corruption. 28 Thou hast made known to me the ways of life; thou shalt make me full of joy with thy countenance. 29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day. 30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne; 31 He seeing this before spake of the resurrection of Christ, that his soul was not left in hell, neither his flesh did see corruption. 32 This Jesus hath God raised up, whereof we all are witnesses. 33 Therefore being by the right hand of God exalted, and having received of the Father the promise of the Holy Ghost, he hath shed forth this, which ye now see and hear. 34 For David is not ascended into the heavens: but he saith himself, The Lord said unto my Lord, Sit thou on my right hand, 35 Until I make thy foes thy footstool.