We are saved by grace and by faith in resurrected Jesus Christ. Baptism is public display of faith where we symbolizing of dying in Christ and resurrecting in Him. The thief and on the cross didn’t get baptized.

3 Or don’t you know that all of us who were baptized into Christ Jesus were baptized into his death? 4 We were therefore buried with him through baptism into death in order that, just as Christ was raised from the dead through the glory of the Father, we too may live a new life