Both what our minds and intellects and what the Quran and hadiths say are good proof that all humans are common in the “gem of humanity” that they possess (meaning that they have the potential of reaching high stages of nearness to God and perfection). Therefore, the “nafsul-amr” religion (the religion that Allah (swt) has legislated for us before it coming down to us) has been legislated in accordance with that common “gem” that we all possess. Conclusion: Allah (swt) has one way for all of us, lacking any diversity whatsoever.
If we consider humans as completely different entities with absolutely nothing in common, or if we consider various groups of people completely different from other groups, one can say that Allah (swt) has a different way of reaching perfection and salvation for each group or individual. But if all humans are common in nature, their true essence and the “gem of humanity” that each and every one of them possesses, despite all of the differences in appearance and on the outside, then the true religion which is referred to as the “nafsul-amr” religion that is supposed to guide them to eternal prosperity and salvation will without a doubt be one as well. Therefore, it can be said that our definition of religion depends on how we explain who man’s true essence.
Both intellectual and narrative reasoning (Quran and hadiths) are good proof that all humans have at least one thing in common, which is the “gem” that was pointed to. On the other hand, since religion has to do with that one thing that all people have in common, there is only one true religion for all people, lacking any sort of diversity.
 Abdullah Jawadi Amoli, Shariat dar Ayneye Ma’refat, pp.93-95.