Imam Hussain (AS) gave everything he had and tried his best to get rid of the oppressive regimes in order that the good can replace the bad. The appearance of Imam Mahdi (AJ) will be for the same purpose. All the prophets rose up in this world for the same purpose. When we see the lives of all of them, from the start, their aim was to stand against tyranny. Therefore, this means their ways must become a role model for Muslims [1].
[1] Sahifaye Imam, Vol. 21, Page 2 (21 March 1988, Imam Khomaini’s message).