So true baptism only is valid after we truly commend our spirits to God. After we really get our hearts into it. And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God. Believing with all our hearts is more than just casual belief and understanding and agreement.
Many people agree the Bible is correct, but never DO it.
They never make it their lifestyles nor do they practice it. They just believe. But believing with all the heart is more than just believing and agreeing with it. The reason some people cannot stay away from sin is because they either feed themselves with those thoughts so much, or else they only go so far in agreement with the Bible, or mental affirmation. Such people tell Jesus, I never promised you a rose garden.