The Baptism of the Spirit empowers believers with other gifts so that they can carry out God’s work. They can witness, teach, preach, serve, etc.
These are two separate actions of the Spirit.
For Christ’s disciples, these two events occurred at well separated times. They were first believers (so that had been converted) and later, after Christ’s Ascension, they received the Baptism of the Holy Spirit at Pentecost.
John explains, at least in part, why these distinct events were also separated in time:
38Whoever believes in me, as the Scripture has said, streams of living water will flow from within him." 39By this he meant the Spirit, whom those who believed in him were later to receive. Up to that time the Spirit had not been given, since Jesus had not yet been glorified. (John 7:38-39)The controversy today between Charismatic and non-Charismatic views is not about the existence of the baptism of the Holy Spirit. The debate centers around its timing.
If you read John 7:39 as referring to Spirit Baptism which was to come at Pentecost, then the gap during the apostolic period had a reason: the baptism had to wait until Jesus had been glorified (why? I don't know). This particular delay between regeneration and baptism (of the spirit) is obviously unique to the apostolic era. For all subsequent generations, Christ is already glorified, and there is no apparent need for a gap between regeneration and spirit baptism. The very fact that John describes the delay, and goes to the trouble of giving a reason for it, suggests to me that the delay is a special, not an ordinary circumstance.
Some (not all) Charismatic denominations accept this delay as normative for all ages. If so, a distinct, identifiable Spirit baptism is expected, and its prolonged absence ultimately affects (despite, in some cases, warnings that it shouldn’t) one’s assurance of salvation.
I don’t read the Bible as teaching that regeneration and spirit baptism are still separated in time. To me, John 7 instructs us that a universal delay was for the apostolic age only. I think if the delay were something that all believers were to expect, the writers of the New Testament would have gone to great lengths to associate such a watershed event with assurance of salvation.
That does not mean that I don’t think it could happen. God will do what He wills for His purpose. I think the evidence is that it is not normative, and I pray for those in Charismatic churches who have not had a genuine experience, including those that have had fraudulent experiences. Do not be anxious for something that has not been promised (a distinct, identifiable Spirit Baptism) as part of God’s plan of salvation. You are likely waiting for something you already received when you were regenerated.