If it is said: But is it not true that the forefathers of the Imam were alive and visible to people and despite this there was risk to their lives, but the circumstances of that time was not that people should have not access to them. We would reply: The circumstances of the forefathers of Imam Mahdi were different, because they acted according to dissimulation (Taqayyah) with the rulers of their times and acted with them in such a way that even the rulers knew that they would not stage an uprising and the Holy Imams also did not see any exigency in staging an uprising. On the contrary, the circumstances of the lives of the Holy Imams show that these personages were also in anticipation of the Mahdi and those who had faith in their Imamate also did not cause any loss to the regimes of their times [it was so, because the Holy Imams were not commanded to stage an uprising]. But the matter of Imam Mahdi is not like this. It is so, because it is known from the circumstances of the Imam that he would stage an armed uprising and finish off the tyrant regimes from the world and subdue all the tyrant rulers and wave the standard of justice and equity on the whole world and destroy injustice and oppression. Thus, if someone is having this quality then certainly the rulers of his time would be terrified and be inimical to him and would pursue him and send spies to observe all his movements; and they would be terrified of this all the time. In such circumstances, Imam needs to keep himself away and in occultation from the people, till the time of his reappearance; from those from whom he perceives danger, whether they are friends or enemies. In addition to what is mentioned, the forefathers of Imam Mahdi were apparent and not in occultation, because if death or martyrdom occurred for them they knew well that after them one of their issues would be the successor, but such a thing is not there for Imam Mahdi . It is so, because if an event like martyrdom occurs before the uprising, there is no one who can be his successor; therefore it was necessary for Imam Mahdi to be in occultation and circumstances of Imam are completely different from those of his forefathers and this matter is absolutely clear. If it is said: How can we understand that it is time of his reappearance and the danger to his life is no more? Can it be through divine revelation, whereas there is no revelation on Imam ? Or through definite knowledge, which does not require contemplation and consideration? It is also clear and obvious that it is opposed to religious duty. Or through Amara and a sign, which becomes a conjecture for him? It is also harmful to the life of the Imam and it casts his life into danger.