Acts 10:44-48 reads, "While Peter was still speaking these words, the Holy Spirit fell upon all those who heard the word. And those of the circumcision who believed were astonished, as many as came with Peter, because the gift of the Holy Spirit had been poured out on the Gentiles also. For they heard them speak with tongues and magnify God.
Then Peter answered, 'Can anyone forbid water, that these should not be baptized who have received the Holy Spirit just as we have?' And he commanded them to be baptized in the name of the Lord. Then they asked him to stay a few days."

In other passages of scripture, we see people believing before baptism (Acts 8:13), receiving the Word before baptism (Acts 2:41), hearing and believing before baptism(Acts 18:8), and in this passage, we see them filled with the Holy Spirit and speaking in tongues before baptism. Can an unsaved, unbeliever be filled with the Holy Spirit? Of course not. Can an unsaved person glorify God with the gift of tongues? Absolutely not. Therefore, we can safely conclude that these people were saved before their baptism.

Paul puts baptism in proper perspective in 1 Corinthians 1:17. It reads, "For Christ did not send me to baptize, but to preach the gospel, not with wisdom of words, lest the cross of Christ should be made of no effect." If Paul wasn't even sent to baptize, then how can it possibly be a prerequisite for salvation? If it were, Paul surely would have been sent to preach the gospel and baptize.

Did you know that Jesus Christ never baptized anyone? John 4:2 reads, "Jesus Himself did not baptize, but His disciples (baptized)."

We can suffice it to say that Jesus didn't come to baptize either. Therefore, we have the two most prominent and influential teachers in Christianity, and in the entire history of the world, and they did not come to baptize. How could baptism possibly be a prerequisite for salvation?
The answer is simple. It cannot be.