When a parent sends a child to college, it requires a great investment. Obviously that parent hopes his child will apply herself to the rigors of her training. Why? Does he hope she will graduate, come home, hang her diploma on the wall, then sit around the house watching television? No! That parent hopes his child will make his investment pay off by starting a good career.
Likewise, when the U.S. military offers a free education to an enlisted soldier, those years of education are considered an investment. The soldier is told, "After you're educated, your nation and government want a certain amount of your time." That trained soldier is expected to serve in the armed forces for a number of years in order to justify the investment.
So it is with the Lord and our afflictions. Everything you go through as a Christian is a training exercise behind which God has a divine purpose. He did not save you so that you could cruise into paradise on a luxury liner; He saved you to prepare you to be of use in His kingdom. The moment you were born again, He enrolled you in His school of suffering. And every affliction, every trial, is another lesson in the curriculum.
Some Christians are in kindergarten. Their afflictions are not difficult to understand and their tests are much easier to endure. Others are in grade school, and they quickly learn that their tests have become a little tougher to face and harder to understand. Others are in college, and their afflictions are much more severe and more difficult to figure out. Still others are in postgraduate school, with years of hard afflictions behind them and many difficult tests looming before them. Their afflictions are the toughest of their lives, and they realize they need Holy Ghost strength to deal with them all.
My point is, God wants veterans of spiritual warfare — people who have been through many afflictions — to prove His faithfulness to the next generation. And every affliction we endure is an investment He is making in us as His veterans.
“Many are the afflictions of the righteous: but the Lord delivereth him out of them all” (Psalm 34:19).