The baptism in the Holy Spirit is the empowering for service that takes place in the life of the Christian. It can take place at the moment of faith in Christ as in the case of the first Gentile convert, Cornelius; but traditionally and experientially it follows repentance, saving faith, and baptism (see Hebrews 6:1-2). It enables a believer to witness to the Lord’s salvation and to demonstrate one or more of the nine gifts, or manifestations, of the Holy Spirit (see I Corinthians 12:7-10). Just as the indwelling Spirit reproduces the life of Jesus, the outpoured, or baptizing, Spirit reproduces the ministry of Jesus.
To illustrate, if I had a glass of water and took a swallow, then the water would be inside me. If, on the other hand, I went down to the beach and stepped into the ocean, then I would be in the water. We receive, as it were, a drink of the Spirit when we are saved, but when we are baptized in the Spirit, it is as if that initial drink becomes an ocean that completely surrounds us.