If some of its parts become infected with spiritual diseas...
If some of its parts become infected with spiritual diseas and every medicine of sympathetic persuasion and rational pleading has failed, and there is a danger that the infection is going to inflict damage to other parts; now the spiritual doctor, (I mean the Prophet or Imam who is guided by Allah), is confident that a surgical operation is essential to save other sections of mankind from harm.
Then, and only then, he will order jihad; and even then it will be limited to that part which is most necessary to remove. However, even when you feel that there is a necessity of a surgical operation, you will not entrust this dangerous task to an unauthorized person. It will be a very foolish and irresponsible act. You can never be sure that the operation is essential unless a qualified doctor tells you so.
Therefore, according to the Ithna-'asheri law, a war cannot be started unless specifically authorized by the Prophet or Imam himself, and that also to the limits prescribed by that Representative of Allah. After all life is a creation of God and it should not be destroyed unless it has been sanctioned by a Representative of God. Q. 34: WHY INTERNECINE STRIFES BETWEEN FOLLOWERS OF ISLAM? You said in your lecture that Islam is based on social justice.
Why has Islam failed to establish practical social justice in the Midle-East where we have seen wars between Iraq and Iran and between Iraq and Kuwait? A: You should not confuse Islam with the Muslims. Social justice needs a society based on Islamic ideals, and that in turn requires a righteous system of government which draws its strength from the Qur'an and sunnah. Nowadays there are nearly forty five "nations" that are populated predominantly by Muslims.
But their system of governance is totally unIslamic. Even the idea of "nation-states" is a legacy of the Kuffar (infidels) of Europe. In the eyes of Islam all Muslims are one nation.
Allah Subhanahu wa Ta'ala says: "Surely this your nation [or religion] is but one nation, and I am your Lord, therefore worship Me." (21:92) But the Europeans sowed the seed of "nationalism" in the minds of the Arabs and nurtured the idea - with the sole aim of dissecting and annihilating the Ottoman empire, which, in spite of all its short-comings and defects, had kept the whole Middle East together under one Muslim ruler.
Look at the map of the Middle East; you will find numerous "nation-states" in it like pieces of a jig-saw puzzle.