How did Imam Hussein (A.S) define enjoining good and prohibiting bad?

It is narrated that Imam Hussein (A.S) delivered a sermon (Khotbah) which according to some scholars it was delivered in Mena. In that sermon, defining the positive results of enjoining good (right) and prohibiting bad (wrong), Imam Hussein (A.S) said: As Wajib duties, Allah (SWT) has started enjoining good and prohibiting bad from Supreme Being, because God knew that if these two religious duties are established, all (other) easy and difficult religious duties will also be established. And that is why enjoining good and prohibiting bad are the invitation to Islam; and they are accompanied with rejecting oppression and oppressors, distributing public wealth and booties (justly), receiving Zakat from its proper place and spend it for appropriate case [1].