Ikmaaluddin: Shaykh Saduq has narrated from his father and Ibne Walid together from Himyari from Yaqtini from Salih bin Muhammad from Hani Tammar that Imam Ja’far Sadiq (a.s.) said:
“There will be occultation for the Master of this Affair [Mahdi]. During this those who remain attached to their religion will be like those who rub their hands on a thorny branch. Then he gestured and said: There is occultation for the Master of this Affair [Mahdi] and every person is duty-bound to fear Allah and remain attached to his religion.”
[The Promised Mahdi, Allamah Muhammad Baqir al-Majlisi, Biharul Anwar, Volume 13 (Old Edition)/Volumes 51-52-53 (New Edition)]