The question I pose is, "Does one have to have the knowledge that baptism is for the remission of sins, for such to occur?"
I understand that if one is taught by one who knows the truth, this would not even be a question. However, I can not logically see the command that one must have this "knowledge" of baptism for such to occur. Please give me your comments.
Let me start by posing other questions. How do we know that baptism saves? Is it the act of getting wet that saves or the fact that it is symbolic of something else? If just getting wet was all that was required, then all men would be saved the first time that they went swimming. I Peter 3:21, "and this water symbolizes baptism that now saves you also—not the removal of dirt from the body but the pledge of a good conscience toward God. It saves you by the resurrection of Jesus Christ." Peter actually explains it pretty clearly. Baptism does not save you because you got wet or even because you became physically clean, but it saves because of its connection to the resurrection of Jesus. Jesus is the one that said to be baptized (Mark 16:16, "Whoever believes and is baptized will be saved, but whoever does not believe will be condemned."). If Jesus and the apostles had not said over and over that baptism is how to connect to Jesus, we would not have known that there was a connection. There is nothing about dipping in water that would make us proclaim that it is the "obvious" way to symbolize a resurrection. It only becomes "obvious" when we read the Scriptures.
Now, there are many synonyms for the idea of being saved. Peter said baptism was for the forgiveness of sins in Acts 2:38 "Peter replied, "Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit." Peter is not contradicting Jesus, he is just saying the same thing in a different way. To have one's sins forgiven is the same thing that Jesus said when he used the word "saved." While I don't think it is necessary that a person understand all the different synonyms for salvation, I do think it is important that they understand at least one.
Some other equivalent statements about baptism: Romans 6:3 "Or don't you know that all of us who were baptized into Christ Jesus were baptized into his death?" Romans 6:5 "If we have been united with him like this in his death, we will certainly also be united with him in his resurrection." Again we are back to the meaning of baptism. It includes being saved, forgiveness of sins, connecting to his death and connecting to his resurrection.
The reason for the baptism at the time of the baptism is also very important. In Acts 19:1-5, "While Apollos was at Corinth, Paul took the road through the interior and arrived at Ephesus. There he found some disciples and asked them, "Did you receive the Holy Spirit when you believed?" They answered, "No, we have not even heard that there is a Holy Spirit." So Paul asked, "Then what baptism did you receive?" "John's baptism," they replied. Paul said, "John's baptism was a baptism of repentance. He told the people to believe in the one coming after him, that is, in Jesus." On hearing this, they were baptized into the name of the Lord Jesus." Here we learn that belief and baptism need to be at the same time. These disciples of John had been baptized, but they had not been baptized while believing in Jesus. Therefore they were baptized again. It is also interesting to note that both baptisms were commanded by God. The reason for the second baptism was not because the first one was illegal, it just did not count.
Let's assume for a minute that the person in question is following the common (and false) doctrine that baptism does not mark salvation, but is required to show "an outward sign of an inward grace". The way this works is that the person believes in Jesus and at the point that he believes, he is saved. Some time later the person is baptized, but it is not in order to be saved, it is just because Jesus said to do it. This person does not believe they are being baptized to have any sins forgiven because that occurred when he first believed. He is not being baptized in order to connect to the resurrection because he believes that he is already going to be raised even if the resurrection day occurs before his baptism. He is not being baptized to connect to the death of Christ because Jesus already died for his sins and has already hung his sins on the cross. So what is left? The only reason left to be baptized is to show everyone else something. Showing everyone else that you are obedient is not one of the reasons Paul, Peter or Jesus had said was a purpose of baptism.
When one fails to be baptized in order to have salvation, forgiveness of sins, and connection to the death and resurrection of Jesus, it may have been an event at which the person got wet, but did it do anything? If Jesus was only interested in making sure everyone got wet after salvation, then wouldn't the person who came to just believe in Jesus and then later went swimming also be saved? Baptism just means immersion in water. It is not the water that saves. It is not the ceremony that saves. It is Jesus that saves. How could a baptism that has no connection to salvation be later substituted as the baptism that brought them to salvation?
That person is not following what Jesus said in Mark 16:16. He is trying to get Jesus to have said, "whoever believes is saved and should be baptized, but whoever does not believe will be condemned." If Jesus had meant his statement to be taken that way, then the whole concept of baptism is not even germane to the sentence. It would have been equivalent to "whoever believes is saved, but whoever does not believe is condemned. By the way, be baptized." If you take baptism out of Jesus' statement on salvation, then it should not matter if one is baptized before or after belief in Jesus. However, Paul showed in Acts 19 that substituting the wrong baptism for the right one could not be done. The fact that Jesus put it in the sentence in the position that he did, says that he expected people to believe that he wanted them to be baptized in order to have their sins forgiven. When a person is baptized "after his salvation", he is telling Jesus, "I don't really believe what you said, I'm substituting my own will." If they later come to a realization that baptism is required, they should also come to the realization that they have not been baptized in the way that Jesus said.