(This post is part of a series on faith and suffering.)
Joni Eareckson Tada spoke in a chapel service at my seminary on “a theology of suffering”. I am always deeply touched, challenged, and humbled whenever I hear Joni speak. I’d encourage you to listen to her in this 30 minute talk.
Here are a few thoughts of my own on how God can use our suffering for a purpose…
As Joni Eareckson Tada words it, “God permits what he hates to achieve what he loves.”  Or as Romans 8:28 states, “And we know that all things work together for good to those who love God, to those who are called according to his purpose.” God can use suffering in a variety of ways in our lives to accomplish his purposes for both us as individuals, and for the entire world.
For example, in the book of Acts (4:29; 8:3-4) we can see that God used the persecution of the church for the spread of the gospel. It made the believers more zealous, and when they were scattered it led to the message going out to even more places.
In this regard, persecution and suffering can have a purifying affect on individual Christians and the church. It proves the genuineness of our faith (1 Peter 1:7). Only a real risk can test the reality of a belief. In the face of suffering, will we trust God and endure in the faith? It proves that our faith was genuine to begin with.
On a similar note, those who go through difficult times often come out on the other side with a stronger and more pure faith. God can use suffering to develop our character. Verses such as Romans 5:3-4 and James 1:2-4 teach us that trials produce patience, perseverance, and character which ultimately make us “complete” in our faith and give us hope. Even in the secular realm, it is often emphasized that hard times can make us stronger.
God may also have a purpose in our suffering that encompasses more than just our individual life. The life of Joseph would be a prime example. Joseph was the victim of evil and suffered at the hands of others. Yet, God used Joseph to save the lives of many people during a great famine, including the lives of his own family. In Genesis 45:5-8, Joseph himself emphasizes that God sent him to preserve life. And in Genesis 50:20, Joseph further states
“As for you, you meant evil against me, but God meant it for good in order to bring about this present result, to preserve many people alive.”
Joseph had all the temptations to become angry, bitter, resentful, cynical or self-pitying. Yet he did not. He simply related all his life experiences, good and bad alike, to the sovereign hand of God for his life.
(On that note…The book “God Meant it for Good” by R.T. Kendall has been recommended to me. Have you read it already? I don’t have a copy yet but am eager to obtain one.)
In Philippians 1:12-14, we can observe a similar theme in the life of Paul. Paul is in jail, yet he emphasizes that the things that have happened to him have turned out for the furtherance of the gospel. The guards were exposed to the gospel, and Paul’s example helped other believers have confidence and boldness in the Lord. As believers, we need to remind ourselves that we are part of a much bigger story of redemption, and God may use our hardship to further the gospel.
Another purpose for our troubles in life is to enable us to comfort others. Second Corinthians 1:4 states that just as God has comforted us, we can likewise comfort others. Once we have experienced a certain type of suffering, it can better enable to reach out to others going through that same type of trouble. “Support groups” are often very effective for this very reason, and as Christians we should excel at comforting others in their afflictions.
God can use suffering to teach us humility and make us dependent on him. It seems that pride and self-sufficiency are insidious sins that haunt us all. Some sins can be conquered, but pride seems to be a life long battle. If we think we’ve conquered pride, it is a sure sign that we have actually not conquered it! The apostle Paul in 2 Corinthians 12:7-10, speaks of his “thorn in the flesh” and that God gave it to him to keep him from becoming conceited and help him rest in God’s grace. He further emphasizes that he took pleasure in infirmities and distress because “strength is made perfect in weakness.”
In closing, Joni E. Tada gives this great summary of how God can use our suffering for a purpose:
God uses suffering to purge sin from our lives, strengthen our commitment to him, force us to depend on grace, bind us together with other believers, produce discernment, foster sensitivity, discipline our minds, spend our time wisely, stretch our hope, cause us to know Christ better, make us long for the truth, lead us to repentance of sin, teach us to give thanks in times of sorrow, increase faith, and strengthen character. It is a beautiful image! 
10/13/2011: Update. Here is a link to an article from the Parchment and Pen blog on God’s purposes in our sufferings. The author takes a different angle or approach which I appreciated. Hope you’ll find it helpful.