When the apostles in Jerusalem heard that Samaria had accepted the word of God, they sent Peter and John to Samaria. When they arrived, they prayed for the new believers there that they might receive the Holy Spirit, because the Holy Spirit had not yet come on any of them; they had simply been baptized in the name of the Lord Jesus. Then Peter and John placed their hands on them, and they received the Holy Spirit.
There is no doubt that in the story of salvation history, Acts comes at a crucial time of change, and therefore there are traditions within the church which read it somewhat differently. For example, the Pentecostal traditional, which through formidable scholars can make the case for their reading and interpretation, which at the heart is not removed and certainly within the orthodox tradition. Although I am part of a tradition which does not read it that way, I can certainly respect and be open to what the Lord might want to teach me and the church through that tradition.
What does seem to be an overriding theme evident here, which is actually not a part of the tradition I grew up with within the faith, is simply that the Holy Spirit, as Father Michael Cupp mentioned, is given in some way to believers through water baptism. Father Michael didn’t get into the nuts and bolts of that, simply mentioning it along the way. But although water baptism does seem to be clearly related to Spirit baptism in the New Testament, which may be a key itself in trying to understand this, it seems evident enough that water baptism itself is more than just a symbol, and that by it, God chooses to either give, or give something more of his Spirit to all who repent and believe in and through Jesus, and in the name of the Trinity: the Father, the Son and the Holy Spirit. The passage quoted above, which was read this past Sunday, is just one example of evidence of that.
Water baptism tied with Spirit baptism seems to be the entry into the church (1 Corinthians 12:13), in a sense, even into Christ himself (Galatians 3:26-27). While I do not at all believe that water baptism is essential to salvation (what is essential is faith), the New Testament post-Pentecost does not know of any unbaptized believers. That is our Lord’s command, and it’s taken for granted that all believers are to submit themselves to it. It is a precious rite, signifying and somehow by the Spirit, identifying us with Christ in his death, burial and resurrection, and so bringing us into the new life in him and as members of his body. Empowered to testify as Christ’s witnesses, and enabled to begin to live and grow in the new life in him, as well as fulfill the tasks to which the Lord calls us.