As any student of the Bible knows, the "Spirit of God" is a prominent feature in its pages. What does God's Spirit do?
It does a number of things:
1) creates and renews(Genesis 1:2, Job 33:4 and Psalm 104:30)
2) convicts us of sin (John 16:8)
3) reveals spiritual knowledge and truth to humans (I Corinthians 2:10-14 and John 16:13)
4) imparts certain spiritual gifts to humans (prophecy, healing, teaching, etc.)
5) makes us God's children (Romans 8:14-15)
6) enables the God who cannot be contained to live within us (I Corinthians 3:16 and 6:19)
7) provides comfort to humans (John 14:16-17 and 26)
8) produces fruit in human lives (Galatians 5:22-23)
9) plants the seed of immortality within humans (II Corinthians 5:1-5)
Note that, in all of these instances, the Holy Spirit is the agent of God's interaction with humans. Notice also that the Holy Spirit accomplishes all of these things without employing coercion or force.
Many folks are tempted to compare the indwelling of the Holy Spirit to demon possession, but there is no comparison. The demon seeks to dictate, coerce and control. The Holy Spirit, however, seeks to guide, direct, inspire, reveal and enable.
Nevertheless, although we have the ability to resist and suppress the Holy Spirit, Scripture warns us that we are on very shaky ground when we do so. (Acts 7:51, I Thessalonians 5:19, I Timothy 4:14 and Hebrews 6:4-6)
"The love of God is shed abroad in our hearts by the Holy Spirit which has been given to us." (Romans 5:5)