Is understanding that baptism is a participation in the death burial and resurrection of Jesus necessary or is knowing the Gospel sufficient? If one knows the Gospel, repents, confesses, and is baptized; but doesn’t understand that he is participating in the death burial and resurrection of Jesus is he just getting wet, or is he becoming saved? Is this a teaching to benefit our understanding or is this understanding necessary? What was the view of the first century church on this?
You raise one of the more difficult and more controversial questions about baptism. The fancy word for this doctrine is baptismal cognizance. Does a person who has truly believed, made Jesus Lord and repented need to have a full and complete intellectual understanding of the significance of baptism at the time of his/her baptism in order for it to "work"? Is it possible for a person to be baptized out of obedience, but be unaware that it is the actual point in time of salvation/forgiveness of sins/receiving the Holy Spirit, and still to be saved?
My answer is that I am not absolutely sure. However, I would lean in the direction of assuming if that a person, in good faith, did all that is required for salvation, but is not fully aware of every doctrinal aspect of the process, he or she is still saved. Just so you know, in the Church of Christ, which is the historical root of the church with which I fellowship, this has not been the common teaching. The common teaching within the churches of Christ is that “cognizance” is required for salvation. In other words, if a person is baptized after belief, confession and repentance, but is not mentally cognizant that this is the actual point of salvation, then that person is still lost and will go to hell, unless he or she is “rebaptized.”
I tend to think that this doctrine is more a result of a sectarian spirit than of good Bible study, although I have seen Colossians 2:12 as a proof text for this belief. I am sure that I was not aware of every doctrinal truth when I became a Christian. I did not know all the ins and outs of biblical theology. I knew little about the kingdom of God. I had not worked out the question of predestination. Yet, I believe at the time of my baptism, I had sufficient faith and obedience to be saved. It is easy to add many requirements which are not in the Bible, but we should be careful not to add to or take away from what God has told us.
For me, I definitely would not even consider baptizing anyone who was not taught this correctly (that it is the point in time of salvation). I also would not admit to fellowship in the church (if it were up to me) anyone who is not willing to accept that baptism is when (not necessarily how) we are saved. I also would ask anyone who was not cognizant of the meaning of baptism when they were immersed to at least consider the possibility of being baptized with knowledge, but I would not insist that such a person be rebaptized or that they are not saved.
As for the first century, I have never seen any evidence at all that this was an issue. If you read the early church father writings, there was not the slightest hint of a doubt or question about baptismal regeneration. If you look at the very early baptismal traditions, the one to be baptized recited a confession which clearly and unambiguously stated that this was the time of their washing and renewal in the Holy Spirit. So, this was simply not an issue because the role of baptism had not been so confused at this early date and we can assume that people were never in doubt that this was when they were saved.