The general prescription of belief in the Quran and Sunnah
Allah Almighty ordered all his servants to enter Islam and adhering to it and warned them of disobeying him. Also he sent His messenger to call to this. Allah told us that the one who follows him is the rightly guided and the one who turns away from his call goes astray. He warned us in many ayahs of apostasy, polytheism and disbelief.
