In the background of Philippians 1:12, you can hear the church wondering how God could allow Paul to become a victim of injustice in such a way that his work as a church planter is hindered. Paul's answer is not to deny the brutality of life in prison but to own up to the reality that prison has become a place where his heart, soul, and mind have thrived. Because as bad as life is—chained to a Roman solider, facing trial and possible execution—God is using his imprisonment to do something really, really good.
From Garbage to Gold
What Paul knows about God is that he really is good and that he is powerful enough to take life's garbage and turn it into gold, as soldiers hear the gospel (1:13), Jesus cannot be ignored in the city of Rome as the Church there grows more bold in their their witness for Christ (1:14) and as Paul sees the possibility of his release from prison (1:19–26).
Now it's important to see that Paul doesn't know if he'll be released because most of the time we can't see how God is turning our circumstances into gold. Paul doesn't know if he's getting out of jail and even when he declares confidently that he will be 'delivered' (1:19), he is not talking about his political freedom. The word 'deliverance' literally means 'salvation', which is not talking about one's effort to secure rescue or blessing by God but refers to the sanctifying work of God in Paul's life. What Paul can see is that God is using his imprisonment to make him into the man Paul believes he is called to be. Prison has been purifying for Paul, making him more and more like Jesus.
So Why Is Life So Hard?
For Paul—and for us—it's not just that God is turning his circumstances to gold. When life gets hard, we can say with confidence, “God is turning me into gold.”
Why is life so hard? Because we need life to be hard. And we need life to be hard because a good and powerful God is able to use the garbage of our difficulties and turn us into gold.