In another hadīth, he said: “Glad tidings to you of the Mahdī from the progeny of Fātimah! He will appear in the west and fill the world with justice.” It was asked: “O Messenger of God! When will it (his appearance) be?” He said: “It will be at the time when judges would receive bribes while the people become debauchees.” It was asked: “What will be the characteristics of the Mahdī?” He said: “HE WILL BE SEPARATED FROM HIS FAMILY AND RELATIVES; HE WILL BE AWAY FROM HIS HOMELAND AND LIVE FAR FROM HOME.” (Iḥqāq al-Ḥaqq, vol. 19, p. 679.)
“O the Messenger of God! When will Mahdi appear?” As you see they [Companions of our Prophet] continuously ask [him]. He said : “It will be at the time when judges would receive bribes while the people become debauchees.” It was asked: “What will be the characteristics of the Mahdi?” He said, “He will be separated from his family and relatives.” He will be all alone. He will leave his homeland. He will come to Istanbul from a city and he will live far from his home. This is the hadith of our Prophet (saas) for Hazrat Mahdi (as). Iḥqāq al-Ḥaqq, volume 19, page 679. This is the reference. Our Prophet says, “When Hazrat Mahdi appears, a period will come to pass for my ummah in which nothing will be left of Islam but its name, and there will be no trace of the Qur’an but its form and outline. That is, the Qur'an will remain only as a Book. People will not practise it and apply it into their daily lives.
Muslims will be called Muslim in name. When asked what their religion is, they will say “Muslim”. But that is it.
“Of all the people they will be the most alien to Islam.” They will not know Islam at all; they are against Islam, distant to It but their names will be “Muslim”. Of course some people are referred here.