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.
The Rabbis tell us that to construct , we sometimes have to destruct. it is logical and true. Yet, isn't destructing bad? It depends , if it has no other purpose, but if it means to build something better then it has a positive purpose. That is why the Rebbe's fragment is telling us: that even bad actions, and bad things can sometimes be the basis for something else that would be/ is positive. Therefore, every thing that exists should be there. Yes, even jealousy! Why? When we see the destructive aspect that jealousy has, we should then learn not to be jealous. In other words, the bad things and actions are there so that we should see the light, and not follow- or do the same. We should base our actions with the light of the Torah, and with that light we are guided to do, act, think the better way. Then we ourselves become the light with the help of the starting light of the Torah. Torah is everything and negative contrasts are part of H's plans as teaching tools.