Prophecies Made by Isa عليه السلام About the Advent of Prophet Muhammad صلى الله عليه وعلى آله وسلم

Narrated to us my father رضي الله عنه: Narrated to us Muhammad bin Yahya al-Attar from Yaqoob bin Yazid from Muhammad bin Abi Umair from Saad bin Abi Khalaf from Yaqoob bin Shuaib from Abi Abdullah عليه السلام that he said: “Between Isa عليه السلام and Muhammad صلى الله عليه وعلى آله وسلم there was a gap of five hundred years out of which for two hundred and fifty years there was neither a prophet nor any learned one from Allah who was apparent. I (the narrator) asked: What did the people follow? The Imam replied: They followed the religion of Isa عليه السلام. I asked: What was their actual condition? He replied: They were believers. Then he said: The earth never remains devoid of a learned one.” 
[Al-Saduq says:] Among those who roamed in the lands in search of divine proof was Salman Farsi رضي الله عنه. He continued to move from one learned to another and moved from one jurisprudence to another and remained in the pursuit of divine secrets. He gained guidance through narrations. He awaited for the Qaim, the Qaim and the chief of the formers and the latters, Muhammad صلى الله عليه وعلى آله وسلم for four hundred years till he received the glad tidings of his birth. When he became certain of deliverance he set out for Tahama and he was take a captive there.