Breakfast with Solomon - Proverbs 17:3
"The refining pot is for silver and the furnace for gold, but the Lord tests hearts"
Clearly the Lord will subtract certain things from your life and add other things to put you under stress and to bring to the surface what is in your heart. God wants to bring up the gunk so He can get rid of it, and He wants to refine the good stuff that is in your life.
The idea that God monkeys with the blessings of your life is hard for many to believe or fathom, but clearly God will bless you in many areas and withhold blessing in another area so that you will have to trust Him.
Understand that the word heart is not your emotions alone, although that is clearly a part of the idea. Heart in the Hebraic mindset is the mind – what you are thinking about and the way you will reason through a problem.
He is really saying that He is going to test you to see how your mind works. Who do you go to for problems? Where is your confidence? How ready are you to ask for help? When you face a problem that you cannot solve or looks in every way impossible, what do you do? Do you give up? Do you get lured into temptation? Do you pray? Do you wait?
He is looking for clear evidence of how you are wired for the purpose of rewarding you, and so that it can become obvious to you that a rewire job is in order.