R.C. Sproul makes a distinction between the regenerative work of the Spirit and the baptism of the Holy Spirit. Not all Reformed theologians come to the same conclusion about how to understand the baptism of the Holy Spirit in the ordo salutis, but I appreciate Sproul’s nuance:
The baptism of the Holy Spirit is not the same as regeneration by the Spirit. Regeneration gives salvation, while the baptism of the Spirit is an empowering for service.
In the Old Testament all believers were regenerated by the Spirit, but only a few received the baptism. We see this in Numbers 11 where God gave the Spirit to seventy of Israel’s elders. At that time Moses expressed a wish that “all the Lord’s people were prophets and that the Lord would put his Spirit on them!” (v. 29).
Moses’ wish becomes Joel’s prophecy. He predicted God would pour out his Spirit on all people. “Your sons and daughters will prophesy, your old men will dream dreams, your young men will see visions” (Joel 2:28). All of God’s people would receive a baptism for service.
 Sproul, R. (2000). Vol. Book two: Before the face of God : Book 2: A daily guide for living from the Gospel of Luke (electronic ed.). Logos Library System; Before the Face of God. Grand Rapids: Baker Book House; Ligonier Ministries.
Interestingly, Sproul refers to the baptism of the Holy Spirit as being inclusive for all of God’s people and for the purpose of service. This is similar to Martyn Lloyd-Jones rationale behind Spirit baptism as being a distinct work from the Spirit’s work in regeneration, and for the sake of empowering service:
So the question which arises is: What does it mean to be filled with the Holy Spirit? Clearly, there are two things, at any rate, which obviously go with this term. It is something that happens which gives authority and power and ability for service and witness. The apostles were given it there at the very beginning, and the result was that they began to speak with other tongues, and Peter, filled with the Spirit, preached his sermon. Then again, after they had prayed, they were all filled with the Holy Spirit and spoke the word of God with boldness. And when Paul was confronted by the opposition of that clever man, the magician Elymas, he was filled especially with the Spirit in order to pronounce a judgment, and the judgment fell upon the man. So it is clear that the filling with the Spirit happens for the sake of service; it gives us power and authority for service.
Lloyd-Jones, D. M. (1997). God the Holy Spirit (241). Wheaton, IL: Crossways Books.
Lloyd-Jones expounds much farther in the referenced work, which I commend for further reflection if interested in his pneumatology.
© 2013, Rick Hogaboam. All rights reserved.