There is nothing wrong with presenting such strung-together arguments as either of the above, if we realize that we are exercising human logic, that our particular argument is not the only one which might be made, and that our own conclusions are not binding on the consciences of others. We will do well to speak humbly when discussing biblical and spiritual subjects -- and we will be wise to do so, in view of the difference between human logic and divine truth. If we speak with humility, other people probably will find our comments more compelling and our arguments more persuasive as well.
It is unnecessary to resort to such arguments as these in order to persuade someone to be baptized. According to the New Testament, water baptism expresses faith-trust in Christ's atoning blood (Mark 16:15-16). The Apostle Paul does not hesitate to describe baptism's ethical implications in terms of Christ's representative death, burial and resurrection (Rom. 6:1ff). Jesus commands that new disciples who come to faith also be baptized (Matt. 28:19). How could anyone who professes to trust Jesus for salvation and to accept him as Lord hesitate to obey whatever he so clearly instructs?