The refining pot is for silver and the furnace for gold, but the Lord tests the hearts. (Proverbs 17:3)
The purpose of a refining pot is to remove the impurities from the precious metals. These impurities called dross are defined as "waste products, worthless, commonplace, or trivial matter." These are the things that are to be refined out of our hearts. Jesus said, "I came to send fire on the earth, and how I wish it were already kindled!" John the Baptist said of Him, "He will baptize you with the Holy Spirit and fire." The convicting power of the Holy Spirit is the furnace of the heart. It is the Holy Spirit that tests the hearts of men by revealing what is in the heart. The prophet Jeremiah tells us, "The heart is deceitful above all things, and desperately wicked." Therefore when our consciences warn us of our ways and our lives are void of peace, it may be because our hearts are being tested in the Refiner's furnace.