What does Luke 23:39 mean?
Luke mentioned two criminals during the march to the cross, and then turned his focus to Jesus (Luke 23:32). Luke returns to the two thieves. They fulfill Jesus' prophecy that He would be "numbered with the transgressors" (Luke 22:37), a sign of the Suffering Servant (Isaiah 53:12). They're also a kind of foil for James and John who asked, "Grant us to sit, one at your right hand and one at your left, in your glory" (Mark 10:37).Matthew says, "the robbers who were crucified with him also reviled him in the same way" (Matthew 27:44) as the crowd and Jewish leaders standing nearby. Mark agrees (Mark 15:32). It seems that one of the thieves changes his mind while the other carries on. The latter hears the rulers laughing at Jesus' claims to save others (Luke 23:35). But the thief adds a twist: why not save him, too?
In truth, Jesus has already saved one criminal this day. By refusing to defend Himself against legal charges to Pilate, Jesus set the stage for the Jewish leaders to demand Pilate release Barabbas, an insurrectionist and murderer (Luke 23:18–25). The Greek wording indicates the robber is completely sarcastic. He doesn't believe Jesus is the Christ. He doesn't believe Jesus can save Himself or anyone else. The thief is dying a horrible, painful death and strikes out without knowing what he is saying.
That doesn't excuse him, however. The second thief is in just as much pain and has just as little proof that Jesus is the Christ. But He does believe Jesus is innocent and, despite his crimes, he fears God. Unlike his counterpart, he takes a leap of faith. He knows he will die, but he asks Jesus for life, anyway (Luke 23:40–43).