"[§10] God said: 'Who is better in speaking than he who appeals to God, does what is righteous and says, "Most certainly I am a Muslim."'¹⁶ This verse explains that there is no position in this world and the next, better and more glorious than that of those who summon to God, and that a condition of the da'wa is that it comes with appropriate actions. If a person has not done righteous acts, he is not suited to be a dâ'î. If a person does not renounce the association with God of other things, and does not affirm the absolute Oneness of Him, does not understand well the declaration of that Oneness but rather continues to compare God to created beings, he cannot be a dâ'î. It is as our lord the Commander of the Believers, may the blessings of God be upon him and on the imams among his offspring, said: 'Dâ'îs in religion distinguish between doubt and certainty'. Distinguishing between doubt and certainty is to separate truth from falsehood. It is possible that he intended it to be between the literal exterior and the inner meaning. Someone who does not know the true and certain, how can he distinguish doubt from certainty, the truth from falsehood? The dâ'î must know the difference between truth and falsehood, so that he can distinguish one from the other, lest he judge the false to be true, and true to be false, and have them accept this judgment from him, leading thereby to the corruption of the da'wa. "

(Source: Klemm, V. and Walker, P. E., A Code of Conduct—A Treatise of the Etiquette of the Fatimid Ismaili Mission, p.40)

16. Qur'an, 41:33