Hadith

Imam Hasan al-Askari (pbuh)

و اَللَّهِ لَيَغِيبَنَّ غَيْبَةً لاَ يَنْجُو فِيهَا مِنَ اَلْهَلَكَةِ إِلاَّ مَنْ ثَبَّتَهُ اَللَّهُ عَزَّ وَ جَلَّ عَلَى اَلْقَوْلِ بِإِمَامَتِهِ وَ وَفَّقَهُ فِيهَا لِلدُّعَاءِ بِتَعْجِيلِ فَرَجِهِ
I swear by Allah that he (Imam al-Mahdi) shall go into an occultation such that none shall be saved [during that period] from destruction, except the person whom Allah, Glorious and Grand is He, makes firm on the belief of his Imamate [of Imam al-Mahdi] and whom He grants the Divine ability (tawfiq) to supplicate for his speedy advent.

Kamal al-Din, v. 2, p. 384