The Work of the Holy Spirit...

Here's a summation of the wonderful work of the Holy Spirit:

The Old Testament reveals much about the Spirit’s activity in creation (Gen. 1:2; Ps. 33:6), revelation (Is. 61:1–3; Mic. 3:8), empowerment (Ex. 31:2–6; Judg. 15:14, 15; Is. 11:2), and inward renewal (Ps. 51:10–12; Ezek. 36:25–27). 

In the New Testament we clearly see the Spirit’s role  as a distinct divine Person, coequal with the Father and the Son. The Spirit’s full ministry began on Pentecost, after Jesus ascended to heaven (Acts 2:1–4). John the Baptist foretold that Jesus would baptize in the Spirit (Mark 1:8; John 1:33) as the fulfillment of a promise made in the Old Testament and repeated by Jesus (Jer. 31:31–34; Joel 2:28–32; Acts 1:4, 5). Pentecost marked the opening of the last era of world history, which will end when Christ returns.

The work of the Spirit is to glorify Jesus Christ by showing His disciples who He is (John 16:7–15) and what He means to them (Rom. 8:15–17; Gal. 4:6). The Spirit enlightens (Eph. 1:17, 18), regenerates (John 3:5–8), sanctifies (Gal. 5:16–18), and transforms (2 Cor. 3:17-18; Gal. 5:22, 23). He gives God’s people what they need to worship God & serve others – the Spirit empowers us (1 Cor. 12:4–11; Eph. 5:18).

At the time they are born again, Christians, believers in Jesus, receive the Spirit and are "baptized" in the Spirit (Acts 2:38; Rom. 8:9; 1 Cor. 12:13). All the gifts for life service that appear subsequently in a Christian’s life flow from this initial baptism in the Spirit, because in this baptism the sinner is united to the risen Christ. 

So, the Spirit is the dynamic power behind all of the Christian life. Gordon Fee points out this broad work of the Spirit:

“...the Spirit's major role in Paul's view of things lies with his being the absolutely essential constituent of the whole of Christian life, from beginning to end. The Spirit thus empowers ethical life in all of its dimensions — personal, corporate, and in the world. Believers in Christ, who for Paul are "Spirit people" first and foremost, are variously described as living by the Spirit, walking in the Spirit, being led by the Spirit, bearing the fruit of the Spirit, and sowing to the Spirit ... the Spirit conforms the believer into the likeness of Christ to the glory of God. The Spirit is therefore the empowering presence of God for living the life of God in the present.” 

~ Gordon Fee, God's Empowering Presence