Every Passion/Resurrection narrative contains its writer's unique theology. Each evangelist looks at Jesus' dying and rising from a different perspective, from the angle he believes his community most needs to view these saving events.
One of Luke's goals is to confront the idea that we suffer only for the things for which we're guilty (Lk 22:14-23:56). Without realizing it, my mother sometimes enunciated such a theology when, after discovering she'd punished me for something which I hadn't done (a rare event!), she'd remark: "That makes up for the times when I didn't catch you!" In other words, no suffering is unjust; there's always a reason for it.
Luke disagrees. Much more than the other three evangelists, he insists Jesus is innocent. Luke doesn't say it personally; he has the characters in his narrative say it.
Pilate, who eventually condemns Jesus to death, proclaims His innocence four times. "I do not find a case against this man....I have no charge against him rising from your allegations....This man has done nothing to deserve death....I have not discovered anything about Him deserving the death penalty." And on a fifth occasion, he mentions that not only he but "neither Herod" has found Jesus guilty.
To the bitter end, Pilate never declares Jesus guilty. He simply decrees "that what they (the crowd) demanded should be done."
Jesus implicitly declares His own innocence when He remarks to the grieving women, "If they do these things in the green wood, what will happen in the dry?"
Even one of those condemned to death with Jesus defends Him with the remark: "We are only paying the price for what we've one, but this man has done nothing wrong."
Finally, Luke, who writes his narrative with a copy of Mark's narrative in front of him, changes the statement of the centurion who witnesses Jesus' death from Mark's "Clearly this man was the Son of God!" to "Surely this was an innocent man!" No one can miss the point of such redaction.
Luke seems to be telling us to stop looking for the cause of Jesus' suffering and death. Like so many times in our own lives, there's no clear reason for the pain. It's not important that we pinpoint the reason, but that we react as Jesus reacts.
Writing about 25 years before Luke, Paul tries to convey the same insight (Phil 2:6-11). He believes the main reason Jesus suffers is because Jesus is a human being. "He (Jesus) emptied Himself," the Apostle writes, "being born in the likeness of a human....He humbled Himself, obediently accepting even death, death on a cross!" Humanity and suffering go hand-in-glove. Those who accept their humanness must also accept the pain which is part of that humanness.
Yet, Jesus' very act of acknowledging and accepting His humanity pushes him beyond His humanity. "Because of this," Paul writes, "God highly exalted Him and bestowed on Him the name (Yahweh) above every other name....Jesus Christ is Lord!" Like Luke, Paul can never separate the death of Jesus from the resurrection of Jesus. The divine "kicks in" only when we reach the depth of our humanity.
Face of flint
Five hundred years before Jesus, Deutero-Isaiah has a parallel experience (Is 50:4-7). He expresses his discovery in his Third Song of the Suffering Servant of Yahweh, an autobiographical reflection on the unjust pain he experiences because he follows God. In the middle of beatings, buffets and spitting, God helps the prophet continue to be the perfect disciple.
"Morning after morning," he proclaims, "Yahweh opens my ear that I may hear." The message he hears more than any other is the command to continue beyond and in spite of the pain. "The Lord God is my help," he states: "therefore, I am not disgraced; I have set my face like flint, knowing I shall never be put to shame."
Following Luke and Paul's theology, we, like Jesus, shouldn't spend a lot of time worrying about the "just cause" of our daily, human suffering. Such an experience is simply the way we uncover the divine breath which God placed in us at our conception.