One day Imam Ali (AS) came out of the Mosque and was passing by a place where animals were kept and saw 30 sheep in there and said:

Swear to God if I had forces to the number of these sheep, I would have ousted the ruler from his office. In the afternoon 300 individuals swore allegiance to Imam Ali (AS) to fight with him until death. Imam (AS) told them: Go and shave your heads and gather in district of Ahjaral Zeet. Imam (AS) shaved his head and went to the designated place, but from all those people except Abudhar, Meqdad, Khadhifeh, Ammar, and Salman no one else turned up. At this time Imam Ali (AS) raised his hands towards the sky and said: O’ God, they have left me on my own, as did Bani Israel to Haroon [1].

[1] Kafi, Vol. 8, Page 33.

Source: en.shafaqna.com