What is the importance for a preacher to memorize the Quranic text and the Prophetic Hadith and to understand their jurisprudence, so that he may distinguish his call from that of the general public and safeguard himself from making judgments without a jurisprudential proof?

A caller to Islam must be equipped with knowledge to invite people to Allah with insight. The foremost knowledge to acquire is the Qur’an and the Sunnah.

Along with the merit of memorizing the Qur’an and the Sunnah, attention must be given to the understanding (fiqh) of hadith. The Prophet, peace and blessings be upon him, said: "Many a carrier of fiqh is not a faqih (a jurist), and many a carrier of fiqh conveys it to someone who is more of a faqih than him." Al-A'mash said to Abu Hanifa: "O company of jurists, you are the doctors and we are the pharmacists."