This belief is well- established and confirmed by the holy verses of noble Quran as well. "And We wished to do a favor to those who were weak (and oppressed) in the land, and to make them rulers and to make them the inheritors." (al-Qasas, verse 5)
Imam Khomeini once said in a historic message in this regard as following:
I present my congratulations to the Muslims and the nation of Iran for the festivity of the 15th Sha`ban that is the birthday of Imam Mahdi. Sha`ban is a great month. In this month, the great Savior of mankind is born.The issue of the disappearance of the Imam is a great matter that makes us to understand some of the issues. One of them is: Real justice should be spread in the world in its true sense. This is a great thing. There is none among mankind except Mahdi for this task- God has preserved him in reserve to carry out this mission when God deems fit his birth stands a great feast for the Muslims and mankind. When Imam Mahdi appear he will set right every perversion. He will bring man from the abyss of depravation. It is said: "He fills the earth with justice after it is replete with tyranny." All the inhabitants over the globe are in perversion. The good and perfect people are having perversion and deviation though they themselves may not be aware of. The conduct, the behavior, the belief, the actions-all is deviated. Man in his performance deviation is evident. Imam Mahdi is assigned to set right all these perversions and deviations. He will remove the torturous and sinuous things. The earth will be replete with justice in its true sense. Therefore, from this point of view, this is a feast for all Muslims. Since Mahdi will guide all the human beings, it is a feast of humanity. He will wipe out truculence and tyranny from the face of earth (Sahifeh-ye Imam, vol. 12, pp. 409-10).
Imam Khomeini made the remarks on the auspicious occasion of Imam Mahdi's birth anniversary. He fills the earth with justice after it is replete with tyranny.
This belief of great significance has been manifested in practical life of the founder of the Islamic Republic during all years of his righteous and sacred life.
For an instance, one of his pupils once complained about the ongoing tough condition and circumstances, and expressed his doubts about the imminent victory during years of struggle for the Islamic Revolution.
The belief for emergence of the contemporary infallible Imam is considered to be a firm pillar of Shia Muslims' beliefs which reminds us of hope, faith, ultimate fortune and victory of good powers.
The great leader of the Muslim world said elsewhere: "I am hopeful that the certain day will approach when the promise of God will come true and the oppressed will become inheritors of the earth.”
These are promises and good tidings of God the Almighty which will never fall short and will fully be fulfilled. According to Imam Khomeini, the victory of goodness shows that the universe never stays impartial regarding the good and bad. It also indicates that creator of this world doesn't remain neutral about the occurrences and happenings of this universe.
Imam had strong belief that the creator of humankind and all other creatures was managing this universe with a very deep perception and wisdom.
For that reason, he sent a historic letter to the former president of the then Soviet union and maintained that the eastern and western blocs were suffering from lack of spirituality and confronted with social moral decline.
The historical facts and figures show that the great Imam's prediction came true in this regard within some years.
We may easily jump to the conclusion that the belief in emergence of the twelfth Imam the saviors hould be interpreted as undertaking serious efforts to launch and establish justice across the world's societies.
In this sense and context, everybody who takes concrete and solid steps to implement real justice, will be considered closely associated to the infallible savior. For that reason, the great Imam closely allied and linked the Islamic Revolution wit.
The revolution of the Iranian people is the starting point for the grand revolution of the Islamic World under the stewardship of Hadrat Hujjah.