David talks about his trials and troubles, saying, broader trials only lead to broader testimonies... and broader test only lead to broader trust.
It wasn't until God afflicted him... that he searched God's way (Psalm 119:67,71)
Affliction can enlarge our trust and testimony OR turn us into a troubled and bitter soul. Troubles either makes us better or bitter. The difference is His presence...
The Lord is his lamp and His presence is what enlightened or illuminated his darkness. "In Your light we see light..." (Psalm 36:9)
Think about our trees down south... they rarely ever see snow or ice. They grow from a seedling to a mature pine or oak that may experience a kiss of snow every 7 to 10 years.
Now think about the trees up north... season after season they see snow storm after snow storm. From time to time they find themselves in blizzards and whiteout conditions. And because they've lived most of their winters with some accumulation of snow they bear the weight of snow with grace and grit. But our southern trees are just not conditioned for it... they struggle to bear the weight of much of any accumulation.
What is God conditioning us for? He's really good at what He does.