If one closes one’s eyes, one will not be able to see. If one blocks one’s ears, one will not be able to hear. However clear the call of truth may be, it can be understood and accepted only if one opens one’s mind to it. God’s inaudible call present in the universe, and the audible expression of that call by the preacher of God’s word, cannot touch those who have closed minds. The call of truth in its pure, unadulterated form is founded on reality; it is in accord with nature. When it is made, none can fail to recognize it. If one hears it with an open mind, one will know in one’s heart that it is nothing else but truth. However, where society is rigidly bound by age-old conventions, people are less concerned with opening their minds to divine realities than they are with supporting the vested interests of the existing system. As God’s emissary, the preacher is neither a representative nor a supporter of the conventional structures of society. His call, being new and unfamiliar, poses itself as a threat to material security. Much as people are urged by him to submit to the will of God, they baulk at doing so, because it would mean demolishing the world they have made for themselves. It is difficult also for him to convey his message to highly placed individuals who are afraid that, if they follow an ‘insignificant’ person, they will thereby suffer some diminution of their own personal glory. The two greatest obstacles then to the success of the preacher are people’s worldliness and arrogance. It is these mental states, which prevent people from accepting the truth; the Quran has called them ‘seals’ over people’s hearts. The minds of those who do not consider the call of truth seriously, who are proud and worldly in their attitude, are covered with an invisible veil which makes them impervious to the truth. When one is prejudiced against something, one cannot see its rationality, even if there are clear signs in support of it.