The Holy Spirit is the third person in the Trinity. He performs a fundamental multidimensional and indispensable role in the salvation of humanity, actively involved in every stage of God's redemptive plan. From the beginning, the Holy Spirit was present in creation process and throughout history; He convicts the world of sin, regenerating the believers and sanctifying them for holy living; He enables believers for effective witness and service; He distributes spiritual gifts for the enrichment of the Church and seals believers as a guarantee of their inheritance; and many more. The methodology adopted in this study is sola scriptura research, employing scriptural review model, and the Bible is the only primary source of data to ascertain the validity and reliability of the research. The paper addresses the indispensable role of the Holy Spirit from the Old Testament through to the New Testament, touching on His indwelling power in the lives the believers who have genuinely received salvation. The study concludes and recommends urgent need for the church of God to deliver intentional and systematic teaching on the doctrine of the Holy Spirit, inclusion of sound pneumagogy of education and pneumatology into the teaching curriculum to equip Christians with a biblical understanding of the Spirit’s person, work, and significance in daily Christian living, discipleship programme that will focus on the person of the Holy Spirit, among others.