Of everything G‑d created in His world, not one thing was created without purpose. —Talmud, Shabbat 77b
For every being, there is a world, different from the world of every other being. For what is a world? It is those things of which any single being is aware.
So that whether it be a human being like yourself, a cow on a farm or a leaf on a tree, it knows only of its Creator, itself, and whatever is essential to its purpose. And that is its world.
And in the world of each one of us, all that exists and all that occurs is that which is essential for us to complete our purpose—to fix up this world.
For G‑d does not create anything without purpose.
Reshimot no. 44.