Rabeinu Bachaye explains to us that this principle that we’re obligated to go in the way of the world and only when we’ve exhausted the derech hateva (way of the world) are we allowed to rely on Hashem is a principle that you’ll see throughout the Torah. Throughout Tanach (Hebrew Bible), over and over, you’ll see Hashem command the Jewish People, you’ll see Moshe Rabeinu command the Jews do whatever you can in the ways of the world, only then are you allowed to rely on the miracle.
For instance, he explains, when Yehoshua brought the Jewish People into Eretz Yisrael (Land of Israel), everyone knew that they were relying on tremendous miracles. The nations within Cana’an at the time were giants living in fortified cities. The Jews fighting against them understood there would be tremendous miracles. As a matter of fact, every battle was won with complete, absolute miraculous results. There wasn’t a single Jew killed in battle. In one battle one Jew died, and the question was who sinned, what went wrong?
So explains Rabeinu Bachaye, if Yehoshua is leading the Jewish People into battle and everyone there knows that there are going to be miracles of unimaginable proportions, why did Yehoshua warn them ahead of time put on your armor, sharpen your swords, get ready for battle? They knew anyway it was going to be a miracle, they knew anyway they were going to win with miraculous ways. Explains Rabeinu Bachaye that this is the operating principle. You have to go b’derech hateva, you have to act in the ways of the world. Only once we’ve exhausted the ways of the world then we rely on the miracle. This is the way that Hashem created the world and this is the way Hashem wants the world to be run. Hashem wants us to use the derech hateva, and we’re supposed to understand that throughout the process Hashem is behind it, Hashem guides it, and Hashem determines the outcome. Our job is to use this world in the ways of the world and our job is to know that Hashem determines every outcome as it should be.