No one is exactly aware of the time of reappearance of Imam Mahdi (may Allah hasten his reappearance) except for Almighty Allah and Imam Mahdi himself and whosoever determines a time for his reappearance is certainly and undoubtedly a true liar and in various narrations from our infallible Imams they have denied those who set a time for Imam Mahdi (may Allah hasten his reappearance) reappearance and cursed them and also ordered the shias to deny and curse such people.
source : erfan.ir
