John 15:26-27 But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of truth, which proceedeth from the Father, he shall testify of me:
27 And ye also shall bear witness, because ye have been with me from the beginning.
Necessity of the Holy Spirit:
Some Christians over emphasize the work of the Spirit and others under emphasize His work and ministry. Scripturally speaking no one can be saved without the work of the Spirit (Jn 6:44; Jn 3:3, 5-8; Tit 3:5). He is constantly working in the lives of God’s children to bring them into the likeness of God’s Son, Jesus Christ. He is in the world and also works in the lives and on the lives of the unconverted.
His ministry to the world:
Jesus said that the Holy Spirit would act upon the world in a three-fold manner (Jn 16:8-11). Reprove means to convince, bring to light; the suggestion of bringing shame to one exposed; to expose a fault. He acts as God’s Agent to draw us into a personal consciousness of our sin, Christ’s righteousness and the absolute certainty of judgment to come. He exposes our sinfulness, hard heartedness and rebellion for what it is and awakens our conscience to the truth we try to deny. When we admit our sin, confess and seek forgiveness He makes us alive spiritually and begins to work in our life (Eph 2:1, 5).
His ministry to believers:
Once we have been born again and made alive spiritually, the Holy Spirit begins to work in us to strengthen, cleanse, instruct, guide and any other thing necessary (2 Cor 5:17). He will guide us into truth (Jn 16:13-14; 1 Cor 2:11-14); guide us in our everyday life, gives us access to the Father and provides assurance (Ro 8:14-16). He will cleanse us of our sinfulness when we ask (1 Jn 1:9); make us new creatures in true holiness (Col 3:10; Eph 4:24); enable us to live a holy life (Eph 3:16; 1 Thes 4:4) and enables us to be cleansed of the inner defilements of our spirit (Ro 8:13). The Spirit also empowers us for witnessing (Acts 1:8) and bearing acceptable fruit to God (Gal 5:22-23; Eph 5:18; Jn 15:2, 5).