The Holy Spirit is the eternal Spirit and Wisdom (Sophia) of God. She convicts of sin and facilitates righteousness. She enlightens and empowers the believer and the church in sanctity, worship, evangelism and service.
The Holy Spirit’s purpose is to exalt Jesus Christ by leading people to him (Jn. 16:14). She initiates the work of restoration (Tit. 3:5), indwells faithful people (1 Cor. 6:19) and ordains them (women and men) as co-workers for the present and coming Kingdom. People are filled with the Holy Spirit as a means of living in a way that is pleasing to God (Eph. 5:18) and are to live faithfully by exercising the gifts she gives to build up the church (1 Cor. 12:7). The Holy Spirit does not possess Christians without their desire, consent, or control. God is the God of order, not chaos, but even at our own peril, his Spirit does not override human free will or force us to do her will. Similarly, the Holy Spirit does not interfere with ministry, but empowers it.
If you have questions or concerns about my use of feminine pronouns for God and Spirit, please see my other entry: Is God Male?