The beginning of the answer inside. Hashem is unity and in his world there cannot be any conflict with His will. In other words, if Hashem rules this world He wouldn’t allow there to anything contrary to His interest, and there is not. This is a faith argument, we must believe that the world is His to such an extent. On Rosh Hashana etc. since they don’t need Shofar etc. on Shabbos there’s a risk that you may carry. Since Pesach needs to be (a Seder) even on Shabbos so it must be that you won’t carry. Page 51-2.
