The baptism of Acts 2:38, when it was in order, was for the purpose of cleansing those who were already saved to bring them back to "fellowship" with the Lord. It served the same purpose as the "confession" of sin which the Apostle John speaks of here:
"This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth...If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness" (1 Jn.1:5-6, 9).
Here John is saying that if we "confess" our sins then we will be cleansed from the things which interrupt our "fellowship" with God. The baptism of repentance was also in regard to confessing sins:
"In those days came John the Baptist, preaching in the wilderness of Judaea, And saying, Repent ye: for the kingdom of heaven is at hand...Then went out to him Jerusalem, and all Judaea, and all the region round about Jordan, And were baptized of him in Jordan, confessing their sins" (Mt.3:1-2,5-6).
All Christians receive the forgiveness of sins when they believe:
"To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins" (Acts 10:43).
When a person believes he is baptized into the body of Christ by one Spirit and are created in "righteousness and true holiness" (Eph.4:24).
That refers to a Christian's "position" in Christ but our "walk" is another matter. In our "walk" sin separates us from our fellowship with God:
" But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear" (Isa.59:2).
So today when we confess our sins those sins are forgiven us but that forgiveness is not in regard to salvation.
When water baptism was in order those who submitted to the rite of water baptism had their sins forgiven but that forgiveness was not in regard to salvation.
how is forgiveness not in regard to salvation?