Is it necessary to verify the soundness of a Muslim butcher's creed, such as his commitment to prayer, before buying meat from him? And is it correct to refrain from eating at the homes of relatives who deal with a butcher whose creed is not trustworthy?

Whoever is born in Muslim lands and resides in Islam is considered a Muslim unless he commits an act that contradicts Tawhid (monotheism), and the default is his innocence. Ignorance of some matters of creed does not cause harm, for the Prophet, peace and blessings be upon him, used to treat anyone who pronounced the two testimonies of faith as a Muslim and then taught him. Knowledge of all attributes or details of the creed is not a prerequisite for one's Islam. Therefore, meat slaughtered by a Muslim butcher is presumed to be ritually slaughtered (dhakiyya). Students of knowledge must teach common people matters of Tawhid and acts of worship.