What is the ruling on someone who does not accept an explicit Islamic law and claims to be a Muslim?

Rejecting the clear and established rulings of Islam after knowing them contradicts the condition of "acceptance," which is one of the conditions of the word of Tawhid (definition), "Lā ilāha illallāh" (There is no deity worthy of worship except Allah). Acceptance means that one does not reject anything that this word signifies; rather, one accepts it truly. So, whoever says "Lā ilāha illallāh" but does not accept its implications or adhere to them, is like the arrogant ones who said: {Indeed, when it was said to them, "There is no deity worthy of worship except Allah," they used to be arrogant} [Surat As-Saffat 37:35]. Submission (inqiyād), which is antithetical to abandonment, is following through actions, and surrendering and yielding to all the conditions of "Lā ilāha illallāh." So, whoever utters the word but does not accept some of what it signifies, out of arrogance or for any other reason, will not benefit from it, such as one who does not accept that worship is for Allah alone, or does not accept the falsehood of the polytheists' religion. And abandoning submission to the rulings of Islam, some of it flaws the very foundation of faith, and some of it flaws its obligatory or desirable completeness.