Requisite Qualities of a Muslim Daʻiyah
Question :
What are the essential qualities that a caller to Islam must possess? And can I become a caller to Islam, even though I have not memorized the whole Qur'an?
Answer:
One who invites to Islam has to know what he is ordering and what he is inviting to. He has to be gentle and patient. But he doesn't have to be one who has memorized the Qur'an in its entirety, nor does he have to be thoroughly acquainted with the fine details of any branch of knowledge.
What is required of him is that he has learned the obligations and prohibitions of the religion that he is inviting others to.
Thereafter, he should learn the proofs that are convincing enough to those he is inviting. It is also befitting for him to learn the methods of oration, and how to make the listener under-Jihad, Da'wah and Commanding Good stand and appreciate what he is calling to.
Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 8 Pages 46-47