The truth that Jesus' enemies – the systems represented by the Jewish council and the Roman governor – need to deny, a convicted thief can see.
The criminals hanging at Jesus' left and right know the system. They understand how charges get trumped up, testimony falsified, the book thrown at common criminals. One looks at the evidence: If this Jesus is who he says he is – the King of the Jews, the Son of Man – he ought to be able to save himself. Since Jesus is still on the cross, dying in pain, he mocks his helplessness.
It's the pain that helps the second thief recognize Jesus for who he is. Pain levels the playing field. In a classic scene in the TV series “Homicide,” a salesman is pushed in the subway and winds up compressed between a train and the platform – condemned yet still alive. As he deteriorates he asks Det. Frank Pembleton, sitting with him while he awaits the rescue that will kill him, “What is the cosmic reason for pain?” “It's the only thing we have in common,” the veteran detective replies, the thing that helps us understand people whose experience is so different from us.
Sure, too, of his own death, the second thief has no reason for illusions, yet he is too realistic for false hope. Unlike the servants of the system who need to dehumanize Jesus to preserve their status quo, this man restores to Jesus his name and his identity, expressing confidence that Jesus' kingdom awaits.
Jesus' radical message still causes the powerful to neuter or dehumanize him. Yet those who are suffering still name him, and hope for his kingdom. Their pain draws them into union with him.