The Medrash continues by citing the verse (Tehillim 75:7): ‘For it is not from the east or from the west, neither from the desert does elevation come. But G-d judges; He humbles this one and elevates that one.’ It explains the words ‘the east and the west’ to mean that one doesn’t become rich by traveling in all directions in order to do business and make money. Even if one travels all around the world, he cannot become rich on his own. The pasuk continues to say that one cannot ‘elevate’ himself. Only Hashem decides who will be lifted up and who will be lowered, who will be granted wealthy and honor, and who will not be.
We also find that Chana said (1 Shmuel 2:6): ‘Hashem kills and makes grants life. He brings down to the grave and raises up. He impoverishes and makes rich. He humbles and He also uplifts.’ He lowers some people and uplifts others according to His will.
The Medrash relates the story of a non-Jewish woman who asked Rav Shimon ben Chalafta how many days Hashem spent creating the world. He answered her that He created the world in six days. She asked, ‘What has He been doing since then?’
Rav Shimon answered, ‘He is sitting and making ladders, which He uses to uplift some people and lower others.’
The Medrash concludes by saying that because the children of Gad and Reuven wanted wealth, Hashem caused the downfall of Midyan and gave their possessions to these tribes. For this reason, the Torah first says that Klal Yisroel defeated Midyan, and then says that Gad and Reuven had much livestock. He took from Midyan and gave to the tribes of Gad and Reuven.