Enjoining Rights & Forbidding Wrong

Ibn Taymiyyah said: "This (enjoining good and forbidding evil) is a duty that the entire Ummah is obliged to fulfill. It is what the Ulama know as an obligation of collective responsibility, if a group in society undertook to discharge it, the other members of this society are absolved from it. The entire Ummah is commissioned to undertake it, but if a group therein was responsible for discharging it, the rest of society is no longer obliged to undertake it."