The Problem of Evil is a perennial problem for those who try to seek God's will. If I seek to follow God, why do I suffer? I pray and grow poor. My neighbor curses God and grows rich? How is this just? This mystery is revealed in light of the Christ: God loved His Son and even He suffered more than any.
Even though I know the theological answer and I accept that redemption involves suffering ("unless you take up your cross daily you are not worthy to be my disciple"), I still struggle against suffering in my soul.
One Psalm in particular is helpful for me - Psalm 72 in the Vulgate (or Psalm 73 in other Bibles). Here, King David laments how the "wicked prosper," and he observes that those who despise God continue to enjoy life. The wicked don't worry about death (v. 4). They don't have to work hard or suffer (v. 5). The wicked are prideful, healthy, and wealthy (v. 6). They curse and blaspheme (vv. 7-9) - think of all those that take God's name in vain repeatedly and yet they prosper upon the earth!
Then David asks in v. 11, "Doesn't God know this? Doesn't God see these people becoming rich and happy?"
David cries out:
Then have I in vain justified my heart, and washed my hands among the innocent. And I have been scourged all the day; and my chastisement hath been in the mornings. I will speak thus; behold I should condemn the generation of thy children (vv. 13-15).
David ponders this problem and he worries about it. But then he finds the answer - the answer is liturgical. Yes, the liturgy of God is what opens his eyes to the truth - a sacramental answer comes from God:
 I studied that I might know this thing, it is a labour in my sight:  Until I go into the sanctuary of God, and understand concerning their last ends.  But indeed for deceits thou hast put it to them: when they were lifted up thou hast cast them down.  How are they brought to desolation? they have suddenly ceased to be: they have perished by reason of their iniquity.  As the dream of them that awake, O Lord; so in thy city thou shalt bring their image to nothing.
David's heart doesn't understand the problem of evil "until I go into the sanctuary of God," and then he "understands concerning their last ends."
Within the Temple, in the presence of God, God realizes that His presence is with His people. He also realizes that God is the judge and that this life does not compare to what has been promised by God to those who remain faithful. The present circumstances do not constitute true happiness or true beatitude. David sees that the wicked will be "brought to desolation" for their crimes.
The rest of the Psalm is beautiful as David reflects on God in the sanctuary:
 Thou hast held me by my right hand; and by thy will thou hast conducted me, and with thy glory thou hast received me.  For what have I in heaven? and besides thee what do I desire upon earth?
 For thee my flesh and my heart hath fainted away: thou art the God of my heart, and the God that is my portion for ever.  For behold they that go far from thee shall perish: thou hast destroyed all them that are disloyal to thee.  But it is good for me to adhere to my God, to put my hope in the Lord God: That I may declare all thy praises, in the gates of the daughter of Sion.
David's desires turn from earth to Heaven. His desire is for God. He body and soul faint for love of God. He realizes that he is made by God to praise God and enjoy Him forever. Note again how the Psalm ends with his desire to worship God: "But it is good for me to adhere to my God, to put my hope in the Lord God: That I may declare all thy praises."
If you struggle with the problem of evil, follow David. Go to Church, kneel before the crucified Savior in the tabernacle and open you heart. The troubles of life and the desire to compare your life to the fortunes of others will fade away. "Thou hast held me by my right hand; and by thy will thou hast conducted me, and with thy glory thou hast received me."
The problem of evil cannot be solved through debate. Rather it won't be solved "until I go into the sanctuary of God."