Though affliction, trials, suffering, and sorrow are difficult to bear in this life, they are not meaningless for the Christian. In fact, as Paul says, God can uses affliction for our good (Rom 8). Thomas Watson, in All Things for Good, lists several ways how affliction works for the good of God’s people. I’ve slightly edited them here.
1) Affliction is our teacher. Affliction teaches us to know ourselves. In prosperity we are for the most part strangers to ourselves. God makes us know affliction, that we may better know ourselves. We see corruption in our hearts in the time of affliction, which we would not believe was there.
2) Affliction draws the Christian away from the love of the world. In prosperity the heart cleaves partly to the world, partly to God. Then God takes away the world so that the heart may cleave more to him in sincerity.
3) Afflictions conform the Christian to Christ. God’s chastening rod is a pencil to draw Christ’s image more lively upon us. Was Christ’s head crowned with thorns, and do we think to be crowned with roses?
4) Affliction takes away the dross of sin. Just like a doctor sometimes prescribes painful methods to get rid of tumors, so God uses afflictions as the painful medicine which heals many spiritual diseases.
5) Afflictions help loosen our grip on the world. When you dig away the dirt from the root of a tree, it is to loosen the tree from the earth. So God digs away our earthly comforts to loosen our hearts from the world.
6) Affliction is a sign of God’s fatherly love. God disciplines those whom he loves. Every stroke of the rod of affliction is a badge of sonship.
Watson lists a few more ways that affliction is one of the teachers God uses in the Christian’s life. Again, though they are difficult to bear and bring tears, they are not useless.
The above quotes and paraphrases above are found in chapter two of All Things for Good.