I'm sure I could provide a solid case that the Spirit's Baptism is an experience that takes place after salvation/conversion. For instance in Acts 8.
"When the apostles in Jerusalem heard that Samaria had accepted the word of God, they sent Peter and John to them. When they arrived, they prayed for them that they might receive the Holy Spirit, because they Holy Spirit had not yet come upon any of them. They had simply been baptized into the name of the Lord Jesus. Then Peter and John placed their hands on them, and they received the Holy Spirit."
-Acts 8:14-17
Here we have people who were most certainly saved and baptized. They were Christians. Go ahead all who doubt, open the Bible yourself, read the verses leading up to the passage, and do your own research. These people were born again, baptized Christians. Yet... they had not received the Spirit. That is just ONE example.
I am also very confident that I could back up the teaching that Speaking in Tongues is the initial physical evidence of the Spirit's Baptism. When the apostles received the Spirit they spoke in tongues (Acts 2:4), the disciples in Ephesus spoke in tongues when Baptized in the Spirit (Acts 19:7). But notice Acts 10: 45-46....
"The circumcised believers who had come with Peter were astonished that the gift of the Holy Spirit had been poured out even on the Gentiles. For they heard them speaking in tongues and praising God."
Take another look at that passage... How did the "circumcised believers" know that the Spirit had been poured out on the Gentiles? They heard them speaking in tongues.
Like I said, I could provide a pretty decent argument for all of this, but it won't mean much to you if you don't place a high priority on evangelism. If you are not of the Pentecostal/Charismatic tradition, chances are all of this will be interesting, challenging, but mostly irrelevant information to you, if you don't put a high priority on witnessing to the lost.
You see, Jesus wants us to share the Gospel. He wants us to "make disciples of all the nations" but He doesn't ask us to carry out this "Great Commission" by our own abilities and talents. He wants us to share the Gospel in the power of the Holy Spirit. To seek and save that which is lost by His power, not our own.
"But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, Judea, Samaria, and to the ends of the earth."
-Acts 1:8
Many believers know the Great Commission, but few are aware of what Jesus said before He gave it.
"And repentance and forgiveness of sins will be preached to all nations, beginning at Jerusalem. You are witnesses of these things. I am going going to send you what my Father has promised; but stay in the city until you have been clothed with power from on high."
- Luke 24:47-49
"Do not leave Jerusalem, but wait for the gift you heard my Father promised, which you heard me speak about. For John baptized with water, but in a few days you will be baptized with the Holy Spirit."
-Acts 1:5
If however, you are passionate about winning the lost for Christ, this teaching is very relevant. Jesus doesn't want you to get frustrated by reading "soul winning" classes, or by buying thousands of Gospel Tracts, or memorizing every rebuttal to the Christian faith. He doesn't want you to live with the frustration of trying, on your own, to get through to those you care about every day. He wants to empower you. He wants you to share the Gospel in the power of the Holy Spirit. That is what makes this relevant.
After the day of Pentecost, Peter stood up and explained to the bewildered crowd what had just happened. It was much more than the "birthday of the church". It was God supernaturally empowering His servants to share the Good News of Jesus Christ. So I leave you with his words, and encourage you to seek out the Spirit's Baptism, and be empowered to live out the calling that God has placed on your life.....
"Fellow Jews and all who live in Jerusalem, let me explain this to you; listen carefully to what I say. These men are not drunk as you suppose. It's only nine in the morning! No this is what was spoken by the prophet Joel:
'In the last days God says, "I will pour out my Spirit on all people, your sons and daughters will prophesy, your young men will see visions, your old men will dream dreams. Even on my servants both men and women, I will pour out my Spirit in those days, and they will prophesy""
-Acts 2:14-18
