The book of Acts follows the story of the apostles after Jesus has finished His earthly ministry; Acts is a loose sequel to the Gospel of Luke. And in the 4th and 5th verses of Acts Jesus tells the disciples to stay in Jerusalem to await the baptism of the Holy Spirit. This is not the first mention of this- The old testament promised the ‘Spirit of God’; Jesus spoke on several occasions of the Holy Spirit and its part in future ministry; And John the Baptist, who Jesus often refers to when talking of the Baptism of the Holy Spirit, also refers to being Baptists in the holy Spirit and Fire [Matt 3:11, Luke 3:16].
John himself was filled with the Holy Spirit; this is mentioned in Luke 1:15. Whether this is the same as baptism in the Holy Spirit is unclear. What does seem significant is that the spirit only ever seemed to be on one person at a time at this stage in history. Elijah (to whom John is often compared) had the spirit much earlier in history; Simeon had heard from the spirit while Christ was an infant [Luke 2:25]. But the moment Jesus’s ministry began John’s ministry was superseded. Christ had the Holy Spirit descend on Him like a dove shortly after John baptised Him [Matt 3:16, john 1:32]. John and his ministry moved into the background after this point.
Many time Jesus talked about His later departure and the coming of the Holy Spirit; these two events are linked, for Jesus claimed that if He did not go the Spirit would not come [John 16:7]. The Spirit is essential for the gospel ministry; it seems to exclusively work through Jesus during His time on earth, and possibly the same with John’s ministry. After Christ’s departure it came to many men and women, including several Gentiles. We seem to have either Jesus of the Holy Spirit.
But what was the Baptism of Fire? Some closely equate this with Pentecost and the flames over the people’s head; possibly it is simply an expression, spirit and fire. But others see this as an alternative for those who do not accept the Holy Spirit. Jesus say only those born of water and Spirit will see the kingdom of God; fire is not mentioned [John 3:5]. Fire may simply be the unimaginable wrath poured out on those who do not repent. This is uncertain, however; surly there will be wrath for the unrepentant, but we do not know whether baptism (immersion) in fire refers to this. The Bible say ‘Baptism in the Holy Spirit and Fire’, rather than ‘or fire’; the matter is uncertain.
Jesus often refers to His truth as ‘living water’ [John 4:14], or the ‘water of life’ [Rev 22:17], the divine answer to what all men thirst for. How this water reconciles with fire is uncertain, but despite being available to all only the repentant will receive the Baptism of the Holy Spirit.