"Remember that we are the Ahlayabaith (the progeny) of the Holy Prophet (s.a.s.), we are his true companions, we are trustees and treasurers of the knowledge grant to him and we are doors through which one can reach this store house of wisdom and learning. It is unlawful to enter a house but through its door, and he who disregards this principle is a trespasser or a thief.
 
They own and possess in their deeds and words the excellence and nobleness which the Holy Quran preaches. They are the treasure houses of Mercy and Benevolence of God and they are the sources from which real wisdom and true knowledge, destined by Him for man, could be obtained.
 
Their speeches contain nothing but the truth. If they do not speak about any subject it is not because they do not know anything about it or any one can speak better but simply because it is advisable not to speak then. It is imperative on the man, who has been destined by God to guide the humanity, to explain things correctly and truly to his followers, should utilize his wisdom for their well being, should think more of the next world and teach people to attach more importance to it, because they are coming from there and have got to go back there."
 

(Nahjul Balagha: Sermons, letters and saying of Hazrat Ali (Second American edition, 1981), Khutba 157, p. 116-117)