A friend and I are currently studying with an individual who is stuck on the fact that baptism is, in his view, clearly not required for salvation and praying Jesus into your heart will do fine. We go round and round and just when he starts to agree with us and we think we have made some progress he talks to his Mom who is a pastor and well we start over. I thought I would see if you had some ideas on how to confront this false doctrine?
If a person doesn't want to see the truth, no amount of evidence will convince them (II Thessalonians 2:11). Thus, the main thing you are aiming for is to encourage the person to see the truth for himself. One suggestion is to write out a statement that this person affirms to be true, such as:
"Baptism is not required for salvation."
Next, with the person, go through verses to define each term.
1) What is meant by salvation?
2) What is meant by baptism?
3) Who determines what is required?
4) Is only one thing required for salvation?
5) If more than one, can only a subset be done to gain salvation or must all be done?
6) What is the purpose of baptism? What does it do for a person?
7) Is baptism required for salvation?
At each step, write out a list of verses that answers the question. Have the person you are studying with write down the answers. Help him find verses relevant to the question. By the time you're done, he should have proved the point to himself and it won't matter what Mom says about the matter.