Allah will separate his [Hazrat Mahdi’s (as)] friends and the chosen ones from the others, in order for the world to be cleansed of the spreaders of corruption and the hypocrites.
(Bihar al-Anwar, Vol. 52, p. 250)
The hadith indicates that the students and helpers of Hazrat Mahdi (as) will work by separating themselves from the unbelievers. Allah will ensure the global spread of Islamic moral values by way of the activities of these people whom He keeps separate from everyone else. In this way, by Allah’s leave, nobody in the world will be left leaving a heretical life. Throughout history Allah has separated many believers from everyone else in order so they can live by their beliefs. Allah will also keep the followers of Hazrat Mahdi (as) separate from the unbelievers.