Rabbainu revealed that faith in HY should be absolutely pure and simple. Lihavdil (to make a strong barrier and distinction) there are heathen religions that quite erroneously demand people to just accept their religion on pure faith. So why exactly (- i.e. everyone feels in their heart the huge difference, but might have some difficulty verbalizing it) is the former so correct and the latter so very wrong?!
HY is the One and Only G-d, He is the absolute entity which all of existence is included in Him. That means that faith in HY is the paradigm of simplicity. So therefore when a person has simple faith, it is faith in the One and only, this is faith in faith itself. There is no need to know more, just that He is the G-d of Israel – for this is the way of stating and establishing this truth that G-d is absolutely One, as His unity is reflected in Israel. Any other religion has some monkey wrench that is thrown in with equations and whatnot, one must accordingly have faith in something other than faith itself, he must have faith in whatever it is they are pushing.
Na Nach Nachma Nachman MeUman!