I still don't understand, nearly 10 years later. At least I don't understand why the Lord allowed my sons to be afflicted with infantile bilateral striatal necrosis. I don't understand why Jonathan died or why Christopher lived. Today he's 16 and nearly totally recovered.
All I understand is this: life is a riddle, which God wants me to experience but not necessarily solve. When I was struggling to solve it, I found (1 Corinthians 13:12), which only makes sense in the original Greek: "For now we see (or understand) through a mirror, in a riddle," the apostle Paul wrote, "but then face to face."
Modern Christians sometimes rush to put God's truth into little boxes, neatly systematized, categorized, organized, and principle-ized, when God's perspective on suffering is too big for any of that. While for some "spirituality" is defined by what you know, God may be more concerned with how you handle what you cannot know.
A riddle loses its mystery and its power, even perhaps its significance, once it is solved. By keeping us in our riddle (every person's riddle is unique) God is helping us learn to walk by faith, and not by sight.