I declare that if the Great Prophet (s) had not trained anybody else except Imam `Ali (`a), it would have sufficed. If the prophet (s) had been appointed to train such a person to hand over to the society it would have been enough. Such a person is unique, he does not have any peer; nobody may ever excel him. Today is the day when he was appointed as our Imam. We had such a (great) person as our Imam. Nobody can ever reach his station.
Sahifa of Imam Khomeini (RA), Volume 11, Page20