Firstly, the earth getting filled with oppression is not the only decisive and unchangeable course for ‘Zuhoor’ (Reappearance). Rather, Reappearance has another course too, which lies in the people’s readiness in accepting the just and universal government of Imam.
Secondly, the two realities of ‘oppression’ and ‘filled’ are“relative” issues.
Thirdly, the mind, the innate nature as well as the civilized call of all prophets and Imams have always been this:
‘Even if the entire world is engulfed in corruption and oppression, one should never withhold from reforming the individual and society.’
Experience too reveals the fruits of these great personalities’ endeavours at such sensitive times by delivering to the corrupt and vicious societies numerous pure and lofty individuals.
Fourthly, the reformers and guides of humanity recommend:
The pious people must strive and endeavour to influence the society and not allow the environment and society to affect them.
Enjoining good and forbidding evil should be given top priority and never forsaken.
“One shouldn’t lose hope of Divine mercy” and support for such despair is itself a major sin. (Qur’an, 12:87)
In describing the duties of ‘those awaiting’, it has come down in a tradition as follows:
About this verse, ‘O you who believe! Be patient and excel in patience and remain steadfast’ (Qur’an, 3:200), Imam Baqir (a.s.) says: It means, you should show forbearance in performing the obligatory acts; must adopt patience in the face of your enemies and should establish connection with your awaited Imam.’
Also, Imam Sadiq (a.s.) said:
“The one who desires to be among the companions of our ‘Qaem’ must await him and must adopt piety and good manners…..” 
To sum up, Imam Mahdi’s (a.t.f.s.) ‘Zuhoor’ and rule possess two background or position. The first position that pertains to good people is reform and piety and the selection rests with them. The other position is oppression resulting from lack of effort and endeavour on the part of common people and is the normal trend in the society. Here, there is no choice and the environmental conditions are forced on them. As per reason and divine commandments, people living during concealment are responsible for selecting and setting firm the first course, first for themselves and then for others.