Q 5: What is the knowledge required for a Da`y (caller to Allah) who enjoins right and forbids wrong?
A : A Da`y who enjoins right and forbids wrong should be wellaware of the religious knowledge, for Allah (Glorified be He) says:
Say (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ): "This is my way; I invite unto Allâh (i.e. to the Oneness of Allâh Islâmic Monotheism) with sure knowledge, I and whosoever follows me (also must invite others to Allâh i.e. to the Oneness of Allâh Islâmic Monotheism with sure knowledge).
The Knowledge here refers to what Allah states in His Noble Book and what is declared by the Messenger (peace be upon him) in the sound Sunnah (whatever is reported from the Prophet). This knowledge is attained by devoting the attention to both; the Qur'an and the purified Sunnah, to know the Commands and Prohibitions of Allah, and learn how the Messenger used to act (peace be upon him) in
calling to Allah and refuting the Munkar (that which is unacceptable or disapproved of by Islamic law and Muslims of sound intellect), as well as knowing the way of his Companions (may Allah be pleased with them). A Da`y should also contemplate this by referring to the books of Hadith, taking good care of the Noble Qur'an, and checking the declarations of the scholars in this matter, for they have elucidated this matter and clarified what should be done. Therefore, whoever undertakes this matter should be attentive to it. He should be deeply acquainted with the knowledge of the Book of Allah and the Sunnah of His Messenger (peace be upon him) to put things in their right places and choose the proper place for Da`wah knowingly. Thus, his enjoining of right will not cause the occurrence of wrong and his forbidding of wrong will not result in worse wrongful acts.
To sum up, he should have the necessary knowledge to put things in their right place.