Why is Torah compared to light? Because it tells us the place of each thing.
Because, in truth, there is no need to change the world. Everything is here.
Each thing has a place, and in that place it is good. Altogether, it is very good, a beautiful world. All that’s needed is a little light.
What is light? Light doesn't add anything or take away. It only reveals the meaning and purpose of all that it shines upon.
Think of your own home. In the dark, there is no way to know what belongs in your closet and what belongs in the laundry, what is ready for use and what is in need of repair. Instead, that which could be washed or repaired is rejected and despised, and your most valuable possessions may become the greatest hazards.
Switch on one little light and a dangerous place becomes a home. With every light you add, you become suddenly wealthier and more blessed.
So too, this world is meant to be G-d’s home. Torah is light. Shine it bright and heal the world.