Luke 23.41 "We (criminals) are punished justly, for we are getting what our deeds deserve. But this man (Jesus) has done nothing wrong."
The one criminal recognized Jesus for who He was, Christ the King. He also knew that Jesus was innocent.
The only perfect and sin-free person to walk this earth was Jesus. Only His death could pay the penalty of death that my sins deserve.
Father... when I feel smug and just in my sins, gently remind me of Jesus Christ and His work on the cross for me. Amen