His power and wisdom entail with respect to prophethood and revealed laws. The latter, meanwhile, permitted a created being to alter what the Creator had prescribed, thus likening the created being to the Creator (1).
The same applies to worship. Christians worship Him through innovations of their own invention for which Allah has sent down no authority. The Jews, however, turn away from worship. Even on the Sabbath, on which Allah commanded them to devote themselves to worshipping Him, they occupy themselves only with their desires. Thus, Christians associate partners with Him, while Jews are too arrogant to worship Him.
Muslims worship Allah alone in accordance with what He has prescribed; they do not worship Him through innovations. This is the religion of Islam with which Allah sent all the prophets: that the servant submit to Allah and to none other. It is the upright faith, the religion of Abraham. Whoever submits to Him and to others is a polytheist, while whoever does not submit to Him is arrogant.
Allah Most High says:
“Indeed, Allah does not forgive associating partners with Him, but He forgives anything less than that for whomever He wills.”
[Surah al-Nisā’: 48]
And He says:
“Indeed, those who are too arrogant to worship Me will enter Hell in humiliation.”
[Surah Ghāfir: 60]
The same applies to what is lawful and unlawful in food, clothing, and the related matters of impurity. Christians do not forbid what Allah and His Messenger have forbidden; rather, they deem lawful such prohibited, impure things as carrion, blood, and pork. They even worship using impurities such as urine and excrement. They do not perform the ritual bath after major ritual impurity, nor do they purify themselves for prayer. The farther a monk among them is from purity and the more contact he has with impurity, the more highly he is esteemed by them.