In the introduction to the first volume of The Seal of the Prophets (Khatim-a Payambaran), it is written concerning the topic of calls to mankind:
"The `calls' that have occurred among humanity have not all been the same, and the rays of their effects have not been of (only) one kind.
"Some calls and systems of thought are one-dimensional, and proceed in one direction; when they appear, they embrace a broad spectrum of people, millions of people become adherents, but then after their time comes to an end they close shop and are entrusted to oblivion.
"Some are two-dimensional, their rays spread out in two directions. While they embrace a broad spectrum of people, and also progress for some time, their range is not confined to the spatial dimension and also extend into the temporal dimension.
"And some others progress in a multitude of dimensions. Not only do we see them attract a broad range of people from human societies and influence them and notice the effect of their influence on every continent, but we also see that they embrace the temporal dimension, that is to say, they are not confined to one time or era. They rule in all their might century after century. Also, they take root in the depths of the human spirit, and the very core of people's hearts is under their authoritative control; they rule in the profundity of the soul and take the reins of the emotions into their hands. This kind of three-dimensional call is the exclusivity of the chain of the prophets.
"What intellectual or philosophical schools of thought can be found which, like the world's great religions, exert their authority over hundreds of millions of people for thirty centuries, or twenty centuries, or, at the minimum, fourteen centuries, and sink deep into their innermost core."
Forces of attraction are also like this: sometimes one, sometimes two, and sometimes three-dimensional.
'Ali's power of attraction was of the last kind. Not only did it attract a broad range of human society, but it was also not limited to one or two centuries; rather, it has continued and extended throughout time. It is a fact that it lights up the pages of the centuries and ages, it has reached the depth and profundity of hearts and souls, in such a way that, after hundreds of years, when he is remembered and his moral virtues are heard of, tears of longing are shed, and the memory of his misfortunes is awakened to the extent that even his enemies are affected and their tears flow. This is the most powerful of attractive forces.
From here it can be understood that the link between man and religion is not a material one, but rather of another kind, the like of which link connects no other thing to the spirit of mankind.
If `Ali had had no divine colouring and had not been a man of God, he would have been forgotten. The history of man bears traces of many champions, champions of speech, champions of knowledge or philosophy, champions of power and authority and champions in the battle-field, but all are forgotten by people, or else completely unknown.
But not only did 'Ali not die with his being killed, he became more alive. He spoke well when he said:
Those who amass wealth are dead even when they are alive, but those with knowledge will remain as long as the world remains. Their bodies may have disappeared, but their images continue to exist in the hearts. (Nahju' l-balaghah: Saying no. 47 )
He said about his own character:
Tomorrow, you will see these days of mine and unknown characteristics of mine will be revealed to you, and after my place has been vacated and someone else has occupied it you will know me." (Nahju 'l-balaghah, Sermon no. 149 )
My own age does not understand my deep meanings,
My Joseph is not for this market. I despair of my old champions,
My Sinai burns for the sake of the Moses who is coming.
Their sea is silent, like dew,
But my dew is storm-ridden, like the ocean.
My song is of another world than theirs:
This bell calls other travellers to take the road.
Many a poet was born after his death,
He opened our eyes when his own were closed,
And journeyed forth again from nothingness
Like roses blossoming over the earth of his grave.
No river will contain my Oman
My ,flood requires whole seas to hold it.
Lightenings slumber within my soul,
I sweep over mountain and plain.
The Fountain of Life hath been given Me to drink,
I have been made an adapt of the mystery of Life.
No one hath told the secret which I will tell
Or threaded a pearl of thought like mine
Heaven taught me this lore,
I cannot hide it from my comrades. 
In fact, 'Ali is like the laws of nature which remain unchanged by time. He is a well-spring of munificence which is never dry, but which rather increases day by day. In the words of Kahlil Gibran (Jubran Khalil Jubran [1300/ 1883 - 1349/1931]), he was one of those personalities who was born before his time.
. Muhammad Iqbal: The Secrets of the Self, translation of R. A. Nicholson, 2nd revised ed., Lahore 1940.