Proverbs 17:3 says, “The crucible is for silver, and the furnace is for gold, and the Lord tests hearts.” Crucibles and furnaces serve to refine metal. They must burn hot in order to do their job. Heat refines the metal.
The author of this Proverb compares the Lord to a crucible or a furnace. The Lord too burns with intense heat, and yet it is a heat no furnace could ever hope to match. Our God is a consuming fire (Hebrews 12:9, Deuteronomy 4:24). Why is it that he burns so hot? It’s because the material on which he works is infinitely more precious than silver or gold – God works on the heart. It’s also because the dross and impurity he will burn away clings with a tenaciousness no physical impurity of metal ever matched – God burns away sin. Should we be surprised then when we encounter burning trials, even extended burning trials, that refine and test our very souls? The obvious answer is, “No,” in fact, we should expect and even welcome such times. It’s no surprise then that Peter writes this: “Beloved, do not be surprised at the fiery trial when it comes upon you to test you, as though something strange were happening to you…For it is time for judgment to begin with the household of God; and if it begins with us, what will be the outcome for those who do not obey the gospel of God?” – 1 Peter 4:12, 17.
Peter raises a sobering but glorious truth. One way or another we will all experience the fire of God. It will either come as his refining work in us – work that leaves us purified and ready for the courts of heaven – or as his eternal judgment on our unrepentant sin. May we experience the fire of God in a life spent following Jesus, and not in eternity under the wrath of God in Hell!
A last point of encouragement for the Christian walking through our Lord’s refining furnace is this: Our God walks with us in the fire. I think there is no better image of this truth than Shadrach, Meshach, and Abed-nego enduring Nebuchadnezzar’s persecuting anger. As these three literally fell into the fire, Nebuchadnezzar noticed they were not alone: “Did we not cast three men bound into the fire?…But I see four men unbound, walking in the midst of the fire, and they are not hurt; and the appearance of the fourth is like a son of the gods.” (Daniel 3:24b, 25). As they walked through the fire of a petty tyrant, these men of faith experienced the protecting presence of God’s angel. Should we expect any less when we walk through the refining processes that our Creator ordains for us? God does not let his children walk alone in the fires that he designs for them to endure. He goes with them…
Here’s a link to a song that you might appreciate relevant to Proverbs 17:3: “Though You Slay Me” by Shane and Shane.
Fix Your Mind 
I especially appreciate your last point that even in our submitting to the refining fire of our God, we have the assurance of His walking beside us and never leaving us to experience it alone. What an awesome promise.
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