What will the Mahdi change?
There is no turning back in the System of Allah. The past is never repeated!
This holds true for individuals for societies and for nature.
What matters is for man to recognize and remember Allah, his essential truth, and live his life accordingly.
The Quran is a timeless message. Therefore just as it was valid 1000 years ago, it will also be valid 2000 years later. This is why it is said the Quran is valid until doomsday.
We must take the timeless message of the Quran, that is we must first purify ourselves from the dirt of duality... Experience the reality of Allah within our own essence.