the author 'esaaf-ur-raghebeen' (page 153) says: 'Mahdi will take out the ark of the covenant and the books of torah from the cave of anthakia and mountain of syria respectively. he will argue with the jews by means of torah and a large number of the jews will surrender to him.
the author of 'yanabi-ul-muwadda' narrates (on page 476) from the author of 'meshkat al-masabeeh' who narrates from abu huraira that the messenger of Allah (s.a.w.a.) said:
'isa-ibn-maryam will descend and will judge with justice. he will destroy the cross and will kill the pork. he will nullify the 'jazia' (poll tax), set free the young camels and will not ride upon them. he will eradicate enmity and will destroy grudge, hatred and jealousy.
author says: that he will nullify the 'jazia' perhaps refers to this point that all the people at that time would be following the religion of islam just as destruction of the cross too is a metaphoric remark in this regard. eradication of enmity, grudge, hatred and jealousy too may mean that these will be obviated between the jews and christians by the blessings of isa-ibn-maryam's descension.
'Allah will restore the religion by means of Mahdi and will produce victories and triumphs for him. then, except for those who say 'there is no god except Allah' «--» none others would be left on the earth...
the author of 'yanabi-ul-muwadda' narrates (on page 476) from shaikh mohyiddin arabi from his book fotouhat-makkiyah (chapter 366) about Mahdi and his ministers and says:-
'Mahdi will emerge when religion would be on the decline. the one who would not accept will be killed and the one who would engage in debate with him will be defeated. he will so reveal the realities of religion that had the holy prophet (s.a.w.a.) been alive, be too would have judged in the same manner. he will eradicate the (false) religions from the face of the earth. then, except for the pure religion, no other religion would remain over the earth.