Just for starters... In very short:
A. Paul never includes it when he preaches the gospel.
B. He specifically separates baptism from the gospel.
1 Corinthians 1
17 For Christ sent me not to baptize, but to preach the gospel
C. People get the Holy Spirit
before baptism.
Acts 10
44 While Peter yet spake these words, the Holy Ghost fell on all them which heard the word.
45 And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost.
46 For they heard them speak with tongues, and magnify God. Then answered Peter,
47 Can any man forbid water, that these should not be baptized, which have received the Holy Ghost as well as we?
D. The Thief neither did any works nor was he baptized, yet Christ promised him Paradise.
E. None of the OT saints were ever baptized, yet they were saved.
F. Did Paul ever say "I'm glad I never preached the gospel to you?" Of course not.
1 Corinthians 1
14 I thank God that I baptized none of you, but Crispus and Gaius;
G. We are baptized in the Body of Christ by the Spirit.
1 Corinthians 12
13 For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
H. Do you see baptism in the following?
John 5
24 Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.
G. If I believe the gospel by listening to a radio broadcast and I know no Christians... can I baptize myself? You see, salvation by grace requires only God and me... salvation by baptism requires God, me,
and a human agent.
The problems with salvation by baptism are many.