As we know, the topic of the baptism of the Holy Spirit can be a very controversial topic. Sadly it can be used like a slogan or even to demean Christians with whom a person disagrees. Usually when something doctrinal is causing controversy, it is best to go and see what the Bible says about it. So what does Jesus say about this particular topic in Acts 1.
The first detail that the Saviour stresses is that this baptism was going to occur in a particular place, Jerusalem. I think this is why he commands his apostles not to leave the city. If any of them had decided to return to Galilee, they would have missed out on this occasion. Of course, the mention of a specific location raises the question as to why it was selected?
One answer to the question is that God is free to bless wherever he wishes. A second answer is that Jerusalem was the climax or goal of the Old Testament perspective, but here in the New Testament it is only the beginning of what God was going to do. A third answer is that the inhabitants of Jerusalem were the ones who had urged the authorities to crucify Jesus, and Jesus here reveals that where sin abounded, grace would abound even more.
A second detail connected to this baptism was that it was going to be experienced by particular people, the apostles of Jesus. Initially, at least, the baptism with the Spirit was limited to them because there is not a suggestion that it was experienced by the other believers out of the 120 who are mentioned in verse 15. This leads us to ask why Jesus limited the baptism to them, and the answer is given in verse 8: they needed spiritual power in order to be the witnesses of Jesus. These men already had the Spirit, but they needed to experience him in a more expansive and powerful way as they went out with the gospel.
A third detail connected to the baptism with the Spirit is that it is connected to a particular promise made by the Father to his Son (v. 4). This takes us back to the eternal counsels when the Father, Son and Holy Spirit interacted with one another concerning their kingdom of grace and glory. One aspect of these counsels was that the Father promised the Son that, upon the completion of his work on earth, he would receive the Holy Spirit in order to continue the development of the church throughout the history of the world.
This statement of Jesus created the anticipation that something great and marvellous was going to take place shortly in Jerusalem and elsewhere, through these men, as they are empowered by the Holy Spirit. And that is what took place.