These well-known metals had intrinsic value in the ancient world. But their value was enhanced by the refining process (“the crucible” and “the furnace”). This process involved heating both metals to high temperatures in order to change their characteristics and extract impurities.
Just like those metals became even more useful and of greater value by their refining, the LORD does the same type of purifying process with (“tests”) our hearts. All three processes are complicated and there is always a lot of heat. But the end product of all three is something beautiful and special.
The LORD’s refining process will make our hearts better. We can either accept it or fight it – and sometimes that is the hardest part of the process!