Mahdi and Jesus in a quote by Prophet Muhammad (PBUT)
Imam Mahdi is a man among the holy prophet Muhammad’s progeny and a man from the descendant of Imam Hussain (PBUH). He is the 12th Imam living among us now according to the Shia belief although we do not know him. It is stated that Imam Mahdi is the last savior of man who will fill the world with justice and equity when he reappears [Read the narration at here] and the holy prophet Jesus will descend from heaven to help him.
May God hasten the reappearance of Imam Mahdi and the holy prophet Jesus (PBUT)
Click on the image to enlarge
Mahdi
“Mahdi [PBUH] is from my progeny and when he reappears, Jesus [PBUH], the son of Mary, will descend to help him. He will follow Mahdi [PBUH] and pray behind him.”
-The holy prophet Muhammad [PBUH]
Al-Amali (of Shaykh Saduq), Vol. 1, p. 287
قال رسول الله صلی الله علیه و آله
“مِن ذُُرَّيتي اَلمهدي اِذا خَرجَ نَزَل عيسَي بنُ مريمَ(عليه‌السلام) لِنُصرتِهِ فَقَدَّمَهُ وَ صلّي خَلفَهُ”
مهدي (علیه السلام) از فرزندان من است، زماني که قيام مي‌کند، عيسي بن مريم (عليه‌السلام) جهت نصرت و ياري او [از آسمان] فرود مي‌آيد و حضرتش را [براي نماز] مقدّم مي‌دارد و در پی او نماز می گذارد
الامالی (شیخ صدوق)، ج 1، ص 287
Read more about Imam Mahdi in Shia and Sunni books and also in the bible at here
