Were there previous Christian writers, prior to [Dietrich Bonhoeffer (4 February 1906 – 9 April 1945) who claimed that Christ's suffering on the Cross contains the answer to the problem of evil?
A little clarity is in order first. The Wikipedia article on the Problem of evil does not cite Dietrich Bonhoeffer as the originator of "cruciform theodicy".
Soul-making theodicy and Process theodicy are full theodical systems with distinctive cosmologies, theologies and perspectives on the problem of evil; cruciform theodicy is not a system but is a thematic trajectory within them. As a result, it does not address all the questions of "the origin, nature, problem, reason and end of evil," but it does represent an important change. "On July 16, 1944 awaiting execution in a Nazi prison and reflecting on Christ's experience of powerlessness and pain, Dietrich Bonhoeffer penned six words that became the clarion call for the modern theological paradigm shift: 'Only the suffering God can help." Classic theism includes "impassability" (God cannot suffer personally) as a necessary characteristic of God. Cruciform theodicy begins with Jesus' suffering "the entire spectrum of human sorrow, including economic exploitation, political disenfranchisement, social ostracism, rejection and betrayal by friends, even alienation from his own family...deep psychological distress... [grief]..." ridicule, humiliation, abandonment, beating, torture, despair, and death.
The ground work of Dietrich Bonhoeffer’s Cruciform theodicy is centuries old.
The Apostle St. Paul gives us glimmers into his thoughts on Christ’s sufferings.
Meditating this mystery, the power of salvific suffering of Jesus Christ on the Cross, the Apostle Paul says:
"In my flesh I complete what is lacking in Christ's afflictions for the sake of his body, that is, the Church." - Colossians 1:24
Pope John Paul II explains these words as follows:
These words seem to be found at the end of the long road that winds through the suffering which forms part of the history of man and which is illuminated by the Word of God. These words have as it were the value of a final discovery, which is accompanied by joy. For this reason Saint Paul writes: "Now I rejoice in my sufferings for your sake". The joy comes from the discovery of the meaning of suffering, and this discovery, even if it is most personally shared in by Paul of Tarsus who wrote these words, is at the same time valid for others. The Apostle shares his own discovery and rejoices in it because of all those whom it can help—just as it helped him—to understand the salvific meaning of suffering. - Salvifici Doloris
Saint Methodius of Olympus (died c. 311) was a Christian bishop, ecclesiastical author, and martyr. He is commemorated on June 20. He wrote the following on the following on the Cross and Passion of Christ.
Methodius, Bishop, to those who say: What does it profit us that the Son of God was crucified upon earth, and made man? And wherefore did He endure to suffer in the manner of the cross, and not by some other punishment? And what was the advantage of the cross?
Christ, the Son of God, by the command of the Father, became conversant with the visible creature, in order that, by overturning the dominion of the tyrants, the demons, that is, He might deliver our souls from their dreadful bondage, by reason of which our whole nature, intoxicated by the draughts of iniquity, had become full of tumult and disorder, and could by no means return to the remembrance of good and useful things. Wherefore, also, it was the more easily carried away to idols, inasmuch as evil had overwhelmed it entirely, and had spread over all generations, on account of the change which had come over our fleshy tabernacles in consequence of disobedience; until Christ, the Lord, by the flesh in which He lived and appeared, weakened the force of Pleasure's onslaughts, by means of which the infernal powers that were in arms against us reduced our minds to slavery, and freed mankind from all their evils. For with this end the Lord Jesus both wore our flesh, and became man, and by the divine dispensation was nailed to the cross; in order that by the flesh in which the demons had proudly and falsely feigned themselves gods, having carried our souls captive unto death by deceitful wiles, even by this they might be overturned, and discovered to be no gods. For he prevented their arrogance from raising itself higher, by becoming man; in order that by the body in which the race possessed of reason had become estranged from the worship of the true God, and had suffered injury, even by the same receiving into itself in an ineffable manner the Word of Wisdom, the enemy might be discovered to be the destroyers and not the benefactors of our souls. For it had not been wonderful if Christ, by the terror of His divinity, and the greatness of His invincible power, had reduced to weakness the adverse nature of the demons. But since this was to cause them greater grief and torment, for they would have preferred to be overcome by one stronger than themselves, therefore it was that by a man He procured the safety of the race; in order that men, after that very Life and Truth had entered into them in bodily form, might be able to return to the form and light of the Word, overcoming the power of the enticements of sin; and that the demons, being conquered by one weaker than they, and thus brought into contempt, might desist from their over-bold confidence, their hellish wrath being repressed. It was for this mainly that the cross was brought in, being erected as a trophy against iniquity, and a deterrent from it, that henceforth man might be no longer subject to wrath, after that he had made up for the defeat which, by his disobedience, be had received, and had lawfully conquered the infernal powers, and by the gift of God had been set free from every debt. Since, therefore, the first-born Word of God thus fortified the manhood in which He tabernacled with the armour of righteousness, He overcame, as has been said, the powers that enslaved us by the figure of the cross, and showed forth man, who had been oppressed by corruption, as by a tyrant power, to be free, with unfettered hands. For the cross, if you wish to define it, is the confirmation of the victory, the way by which God to man descended, the trophy against material spirits, the repulsion of death, the foundation of the ascent to the true day; and the ladder for those who are hastening to enjoy the light that is there, the engine by which those who are fitted for the edifice of the Church are raised up from below, like a stone four square, to be compacted on to the divine Word. Hence it is that our kings, perceiving that the figure of the cross is used for the dissipating of every evil, have made vexillas, as they are called in the Latin language. Hence the sea, yielding to this figure, makes itself navigable to men. For every creature, so to speak, has, for the sake of liberty, been marked with this sign; for the birds which fly aloft, form the figure of the cross by the expansion of their wings; and man himself, also, with his hands outstretched, represents the same. Hence, when the Lord had fashioned him in this form, in which He had from the beginning flamed him, He joined on his body to the Deity, in order that it might be henceforth an instrument consecrated to God, freed from all discord and want of harmony. For man cannot, after that he has been formed for the worship of God, and has sung, as it were, the incorruptible song of truth, and by this has been made capable of holding the Deity, being fitted to the lyre of life as the chords and strings, he cannot, I say, return to discord and corruption.
It is evident that for St. Methodius the Cross and the sufferings of Christ contained the answer to the question of the problem of evil and more: our salvation.