I believe there are some misunderstanding of scripture here. The thief on the cross never died under the new law (law of liberty) Galatians 5:1-7. You see Christ first had to die before the law was established (Hebrews 9:16-17). We see that the blood of Christ must be shed for ours sins (Hebrews 8). The thief died under the old covenant where baptism wasn't required. If you say that baptism isn't required, you neglect the verse 1 Peter 3:21, where the word "also" means "and". In addition to this verse, why was everyone under the new covenant, all the way through the new testament baptist and mentioned. People say that faith is all you need to be saved. My friend the devils in James 2:19 also believed and trembled. Why is Mark 16:16 even in the bible. I would take another look into this and i would be glad to discuss it further.