One criterion is that there were seemingly two conflicting and paradoxical sets of characteristics in the Commander of the Faithful: the first was steadfastness, resistance, and strictness; another was leniency, compassion, and clemency. These qualities existed in the Commander of the Faithful to their perfection. He was steadfast and strict in the face of every evasive course of action. In the face of oppression, oppressors, deviation from the path of God, transgression, and greed: the Commander of the Faithful would stand up against these matters with complete steadfastness and power; his resistance against those conditions is unprecedented, to this very day. He also behaved in a completely sensitive and delicate manner when it came to divine remembrance and dhikr; he behaved similarly towards the oppressed, underprivileged, and vulnerable classes of society.
At all stages of life, he is our role model. Teenagers who are ten, twelve, thirteen years old can follow Ali (a.s.). They can make him their role model. Why? Because when he was ten,eleven years old, he was the first person to know and accept Islam and follow the Holy Prophet (s.w.a.).
The fact that a ten, eleven-year-old child discovered the truth, stood up for it and followed it as hard as he could, amid all those hostilities and denials, is very important. Young individuals who are twenty, twenty-two, twenty-five years old can also make the Commander of the Faithful (a.s.) their role model. Why? Because when he was twenty-three years old – during the time when the Holy Prophet (s.w.a.) migrated from Mecca to Medina – he undertook the heaviest responsibility during the great migration.
The Holy Prophet (s.w.a.) entrusted the dearest members of his household to Ali (a.s.) so that he would bring them from Mecca to Medina. The Holy Prophet (s.w.a.) entrusted him with the duty of giving the people things which were held in trust, pay his debts, get the money which the people owed the Holy Prophet (s.w.a.) and join him in Medina. And it was he who agreed to sleep on the Holy Prophet’s (s.w.a.) bed and face danger during the night when the enemies were supposed to break into the house and mutilate the Holy Prophet (s.w.a.) with their swords. See how great that Imam (a.s.) was. This can become a model for us.
http://shiastudies.com/en