It has long been noted that Jesus believed he needed to suffer to fulfill God’s plan, such as demonstrated with the desperate Gethsemane prayer, or Jesus rebuking his followers for not thinking he had to suffer. This has sometimes been thought to be due to an exegetical coloring of the gospels with Isaiah 53, although there is disagreement on this issue.
Here is another avenue that might prove more fruitful as an explanation. In Book 2 of Plato’s Republic, Plato gives the example of the lowly impaled just man as a condition to determine whether one was truly just and whether this is preferable to being a happy unjust ruler. Sachs comments that:
If Socrates were to succeed in proving that justice by itself cannot but be good for the soul of its possessor, and injustice evil, he still would not be meeting Glaucon’s and Adeimantus’ challenge; for they ask him to show that justice is the greatest good of the soul, injustice its greatest evil. Further, showing this will not be sufficient unless Socrates thereby shows that the life of the man whose soul possesses justice is happier than the life of anyone whose soul is unjust. The latter is required of Socrates when Glaucon asks him to compare certain lives in terms of happiness. Glaucon envisages a just man’s life “bare of everything but justice. . . . Though doing no injustice he must have the repute of the greatest injustice . . . let him on to his course unchangeable even unto death . . . the just man will have to endure the lash, the rack, chains, the branding-iron in his eyes, and finally, after every extremity of suffering, he will be [impaled].” On the other hand, the unjust man pictured by Glaucon enjoys a position of “rule in the city, a wife from any family he chooses, and the giving of his children in marriage to whomsoever he pleases, dealings and partnerships with whom he will, and in all these transactions advantage and profit for himself,” and so forth, including a not unreasonable expectation of divine favor. Socrates has to prove that a just man whose condition is that described by Glaucon will still lead a happier life than anyone who is unjust if he is to show that, in terms of happiness, which is the Platonic criterion for the choice among lives, one ought to choose the just life. Again, if Socrates is able to show that an unjust man who enjoys the existence depicted by Glaucon is more wretched than any just man, that will suffice for choosing to reject any unjust life. As Prichard remarked, "Plato certainly did not underrate his task. Indeed, in reading his statement of it, we wonder how he ever came to think that he could execute it.
So Plato proposes a sort of test for how to measure whether one is truly just, and whether such an individual would be “happier” in the technical Platonic sense.
Plato’s Republic was the most famous book in the ancient world, so it is not unreasonable to suppose some of its themes may have influenced Jesus and his followers, even if none of them ever read The Republic. Perhaps Jesus thought it was God’s plan for him to nobly suffer as a criminal in society’s eyes like Plato’s impaled just man, because this would demonstrate him to be truly just and thus worthy of being the Son of Man/judge of people in the new age following the apocalypse.