I've just been considering this very topic too. And I've found it very exciting.
I saw in the scriptures that in the various accounts in Acts a number of verbs or expressions were used to describe the same experience.
For example Acts 1:5 For John truly baptised with water and you shall be baptised with the Holy Spirit not many days hence. (Jesus anticipating Pentecost)
The fulfillment to Jesus'words came in Acts 2:4 And they were all filled with the Holy Spirit and began to speak in other tongues as the spirit gave them utterance.
So "being filled with the Spirit" is the same as being "baptised with the holy spirit".
Then Peter quotes Joel to tell the crowd what just happened. Acts 2:17 It shall come to pass in the last days, says God, That I will pour out my spirit on all flesh. So he
related this "pouring out" to what had just happened to them.
Now the crowd had been attracted by the noise of 120 people all speaking in tongues.
Peter said in Acts 2:32-33 "This Jesus God has raised up, of which we all are witnesses. Therefore being exalted to the right hand of God, and having received from the Father the promise of the Holy Spirit, He poured out this which you now see and hear. "
The crowd said, "What shall we do?"
Peter said, "Repent and be baptised every one of you for the remission of sins and you shall receive the gift of the Holy Spirit. For the promise is to you and to your children
as many as the Lord our God shall call.
So in this one passage four different expressions are used to describe one experience: baptised with the Holy Spirit (1:5), filled with the Holy Spirit (2:4), the spirit was to
be 'poured out'(2:17), and receive the gift of the Holy Spirit (2:38).
We can also look at Acts 8:15-18 three different expressions are used to describe one experience when the Samaritans were saved: receiving the Holy Spirit (v15, 17 and 19), He had fallen upon none of them (v16), and
through laying on of the apostles'hands the Holy Spirit was given.
Acts 10:44-48 is even clearer. Notice the different expressions used to describe what happened.
While Peter was still speaking these words, the Holy Spirit fell upon all those who heard the word.
And those of the circumcision who believed were astonished, as many as came with Peter, because the gift of the Holy Spirit had been poured out on the Gentiles also.
For they heard them speak with tongues and magnify God. Then Peter answered,
"Can anyone forbid water, that these should not be baptized who have received the Holy Spirit just as we [have]?"
Then in
Acts 11:15 And as I began to speak, the Holy Spirit fell upon them, as upon us at the beginning.
Acts 11:16 Then I remembered the word of the Lord, how He said, 'John indeed baptized with water, but you shall be baptized with the Holy Spirit.' (as Jesus had said earlier as recorded in Acts 1:5 (which hadn't been written at that time))
Acts 11:17 If therefore God gave them the same gift as [He gave] us when we believed on the Lord Jesus Christ, who was I that I could withstand God?"
Acts 11:18 When they heard these things they became silent; and they glorified God, saying, "Then God has also granted to the Gentiles repentance to life."
Thus the baptism of the Spirit that the Gentiles had just received was proof that they had been granted repentance by God.
In Acts 11:15 Peter is also clearly stating that Pentecost was the beginning (Not John 20:22 as many say) because Jesus also said in John 16:7 Nevertheless I tell you the truth. It is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I depart, I will send Him to you. and John 7:39 But this He spoke concerning the Spirit, whom those believing in Him would receive; for the Holy Spirit was not yet [given], because Jesus was not yet glorified. )(Here Peter is saying the time they believed was Pentecost.) (Which agrees with Mark 16:16)
In Acts 19:2 & 6 The verbs 'received' and 'came on them' are used and Paul refers back to John the Baptist who said , "I Baptise you in water unto repentance but He who is coming after me will baptise you with the Holy Spirit and fire." (Matt 3:11; Mark 1:8; Luke 3:16 and John 1:33) The fact that this statement of John the Baptist's appears in all four gospels shows it was the main message of John.