I know water baptism does not save a person. Yet why does Peter tell the Jews in Acts 2:38 to “repent, and let each of you be baptized in the name of Jesus Christ for the forgiveness of your sins; and you shall receive the gift of the Holy Spirit?” Those that believe in baptismal regeneration cite this scripture as proof that baptism is what causes your sins to be forgiven. However, it is clear in Acts 10 when Cornelius believes he is instantly baptized by the Holy Spirit and then gets water baptized. Acts 2:41 seems to indicate that only those who believed Peter’s message were baptized. But I would appreciate your Hebrew insight into what you think is happening in Acts 2:38.
Concerning your question about Acts 2:38, it should always be kept in mind that this statement is being made to the same Jewish generation guilty of the unpardonable sin and facing the judgment of A.D. 70. While the coming judgment of A.D. 70 was by now unavoidable, individuals could escape the judgment if they would do two things.
First, they would have to repent, change their mind about Jesus, and that act of repentance would save them spiritually, but by itself would not save them physically.
The second thing they would have to do is undergo water baptism that will separate them from the Jewish generation guilty of the unpardonable sin and therefore, they would escape the judgment of A.D. 70.
This becomes especially evident if you also look in verse 40 where he admonishes them to “save yourselves from this crooked generation”. It is obvious they could not have saved themselves spiritually, because spiritual salvation is a result based upon their faith in Christ. But they could save themselves in another way. He specifies they could save themselves “from this crooked generation” and that is what water baptism will do for them: It will separate them from the generation guilty of the unpardonable sin.
So taken in context, he is dealing here with physical salvation and not spiritual salvation.