A tricky question:
Most Pentecostal denominations believe there are two separate events.
The "indwelling" of the Holy Spirit which happens immediately at the instant of Salvation.
..and then the "baptism" of the Holy Spirit, which could happen years later, ( or even seconds later )
Acts 1:3; To these He also presented Himself alive after His suffering, by many convincing proofs, appearing to them over a period of forty days and speaking of the things concerning the kingdom of God.
Acts 1:4; Gathering them together, He commanded them not to leave Jerusalem, but to wait for what the Father had promised, "Which," He said, "you heard of from Me;
Acts 1:5; for John baptized with water, but you will be baptized with the Holy Spirit not many days from now."
Jesus was speaking to the apostles here. Were they not saved before this conversation? ...and yet Jesus says you will be baptized by the Holy Spirit at some point in the future.
Acts 1:13; When they had entered the city, they went up to the upper room where they were staying; that is, Peter and John and James and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, and Simon the Zealot, and Judas the son of James.
Acts 1:14; These all with one mind were continually devoting themselves to prayer, along with the women, and Mary the mother of Jesus, and with His brothers.
Acts 1:15; At this time Peter stood up in the midst of the brethren (a gathering of about one hundred and twenty persons was there together), and said,
Then we have the upper room, with about 120 people there, including Mary and the apostles. Were none of these people saved?
Acts 2:2; And suddenly there came from heaven a noise like a violent rushing wind, and it filled the whole house where they were sitting.
Acts 2:3; And there appeared to them tongues as of fire distributing themselves, and they rested on each one of them.
Acts 2:4; And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit was giving them utterance.
... the apostles had followed Jesus for 3 years, and yet they don't get baptized in the Holy Spirit until this chapter. Were they not saved before this day?
Acts 8:14; Now when the apostles in Jerusalem heard that Samaria had received the word of God, they sent them Peter and John,
Acts 8:15; who came down and prayed for them that they might receive the Holy Spirit.
Acts 8:16; For He had not yet fallen upon any of them; they had simply been baptized in the name of the Lord Jesus.
Acts 8:17; Then they began laying their hands on them, and they were receiving the Holy Spirit.
These were obviously believers, who had already been baptized ( in the name of the Lord ), but they had not yet received the Holy Spirit. This is 6 chapters after Acts 2.
Then we have Cornelius.
Acts 10:1; Now there was a man at Caesarea named Cornelius, a centurion of what was called the Italian cohort,
Acts 10:2; a devout man and one who feared God with all his household, and gave many alms to the Jewish people and prayed to God continually.
Acts 10:3; About the ninth hour of the day he clearly saw in a vision an angel of God who had just come in and said to him, "Cornelius!"
It seems he is also a believer, and had been for a while. But yet he doesn't get baptized in the Holy Spirit until....
Acts 10:44; While Peter was still speaking these words, the Holy Spirit fell upon all those who were listening to the message.
Acts 10:45; All the circumcised believers who came with Peter were amazed, because the gift of the Holy Spirit had been poured out on the Gentiles also.
Acts 10:46; For they were hearing them speaking with tongues and exalting God. Then Peter answered,
Acts 10:47; "Surely no one can refuse the water for these to be baptized who have received the Holy Spirit just as we did, can he?"
We also have the disciples at Ephesus.
Acts 19:1; It happened that while Apollos was at Corinth, Paul passed through the upper country and came to Ephesus, and found some disciples.
Acts 19:2; He said to them, "Did you receive the Holy Spirit when you believed?" And they said to him, "No, we have not even heard whether there is a Holy Spirit."
Acts 19:3; And he said, "Into what then were you baptized?" And they said, "Into John's baptism."
Acts 19:4; Paul said, "John baptized with the baptism of repentance, telling the people to believe in Him who was coming after him, that is, in Jesus."
Acts 19:5; When they heard this, they were baptized in the name of the Lord Jesus.
Acts 19:6; And when Paul had laid his hands upon them, the Holy Spirit came on them, and they began speaking with tongues and prophesying.
Acts 19:7; There were in all about twelve men.
They didn't even know there was a Holy Spirit. Again, obviously they were believers, who had already been baptized in water. ( John's baptism )
But yet they had never received the baptism of the Holy Spirit until this moment. They could have believers for years before this time.
John the baptist, said water baptism, and the Holy Spirit baptism were two different things.
Matt 3:11; "As for me, I baptize you with water for repentance, but He who is coming after me is mightier than I, and I am not fit to remove His sandals; He will baptize you with the Holy Spirit and fire.
Luke 3:16; John answered and said to them all, "As for me, I baptize you with water; but One is coming who is mightier than I, and I am not fit to untie the thong of His sandals; He will baptize you with the Holy Spirit and fire.
There is a verse that says we don't receive the Holy Spirit unless we specifically ask for it.
Luke 11:13; "If you then, being evil, know how to give good gifts to your children, how much more will your heavenly Father give the Holy Spirit to those who ask Him?"
There is another verses that says you must obey God to receive it.
Acts 5:32; "And we are witnesses of these things; and so is the Holy Spirit, whom God has given to those who obey Him."
Finally we have Saul/Paul on the road to Damascus. Now He was a Pharisee, he did believe in God, but not Jesus so much before this trip.
It was three days later when received Damascus.
Acts 9:9; And he was three days without sight, and neither ate nor drank.
Acts 9:17; So Ananias departed and entered the house, and after laying his hands on him said, "Brother Saul, the Lord Jesus, who appeared to you on the road by which you were coming, has sent me so that you may regain your sight and be filled with the Holy Spirit."
Why didn't Paul receive the Holy Spirit at the moment he met Jesus on the road to Damascus?
In fact, I don't see a single place in the Bible... where the phrase "received the baptism of the Holy Spirit" happens to anyone who just got saved at that instant.
Now I do believe they could happen a few seconds within each other. But it's obvious in the Bible, they are two separate events.