The Appearance of Hazrat Mahdi (as) after the hypocrites have left

Sulayman ibn Bilâl says: Imam Jaffar Sadik narrates from his father, and he from his grandfather, that Hazrat Hussein said: One day, a man came to Ali, the Commander of the Faithful, and said: “O, Commander of the Faithful! Tell us of Hazrat Mahdi (as).” And he replied: “HE IS THERE (HE WILL APPEAR IN A FAR-DISTANT PLACE) WHEN THOSE WHO MUST LEAVE GO, AND WHEN BELIEVERS ARE FEW AND THE TROUBLEMAKERS HAVE GONE.” (Sheikh Muhammad ibn Ibrahim Numani, al-Ghaybah al-Numani, p. 250)