Proverbs 4:18 But the path of the just is as the shining light, that shineth more and more unto the perfect day.
This is an odd simile. It is strange to compare a path to a light. It is saying that your path shines like a light for others to see the way. The Way is Jesus. He reflects His light through us so that others can see God and be saved. And the promise declares that this path light will shine brighter and brighter until the perfect day, the day when we become perfect, the day we die.
Jesus declares, “You are the light of the world….Let your light shine before others, so that they may see your good works and give glory to your father who is in heaven [Matthew 5:14, 16].” This is a promise, not a command: you cannot become a light, you already are. You don’t shine it. Just don’t hide it under a bushel. Let it shine. The light that is in you is the light and life of Jesus, the Wisdom of God. Even others notice, they glorify God.
We do not normally see our own light shining nor notice the effect. But we take it as a promise coming true. Light shines and has an effect. The conditional part of the promise is “be just.” This refers to the believer: “The just will live (shine) by faith.” We believe: we are just: we live: we shine. This is a result of the condition in verse 13: “Take fast hold of instruction, for she is thy life.”