As God the Father promised the Holy Spirit to the early Church, so He still promises that same Spirit to the Church today (Acts 1:4, 5). Anyone who becomes a new creation in Christ possesses the Spirit of Christ the moment of conversion. This is the baptism of the Holy Spirit.
You can think of baptism as an immersion. An image that comes to mind is that of a child jumping into a swimming pool on a hot, summer day. The child is immersed into the water and becomes fully engulfed. In like manner, when a sinner becomes a saint, he or she is fully engulfed or submerged into the Spirit of God. He or she becomes “fully wet” or baptized in the Spirit.
John the Baptist baptized or immersed the repentant in water. The purpose of John’s baptism was designed to bring people to confession of sin and repentance. But an additional purpose for John’s baptism was for people to place their faith in Jesus Christ (Acts 19:4). John the Baptist attested to this truth (Matthew 3:11; Luke 3:16).
The baptism of the Holy Spirit is the descension of God the Spirit onto individual believers. As John’s baptism is the shadow of the change which God brings in the heart and mind of a person, the baptism of the Holy Spirit is the essence of regeneration. It is the progression of God being with man; cleansing and making him or her into a new creature (II Corinthians 5:14-21). Every believer in Christ has God Himself living on the inside of their being.
The Spirit’s baptism is a part of God’s restoration of His kingdom upon the creation, but it is not the final part. There is a time to come in which God will completely reclaim Lordship over all things. This time is when Christ returns. In the meantime, God continues to change His elect through His Spirit. Having the Holy Spirit within them, believers have the power of God.