The believers, men and women, are Auliya' (helpers, supporters, friends, protectors) of one another, they enjoin (on the people) Al-Ma'ruf (i.e. Islamic Monotheism and all that Islam orders one to do), and forbid (people) from Al-Munkar (i.e. polytheism and disbelief of all kinds, and all that Islam has forbidden)
[Quran 9:71]