Mahdi is from the Ahlul Bayt (as)

The Prophet (sawa) said, Even if the entire duration of the world’s existence has already been exhausted and only one day is left (before the day of judgment), Allah will expand that day to such a length of time, as to accommodate the kingdom of a person from my Ahle Bayt who will be called by my name. He will fill out the earth with peace and justice as it will have been full of injustice and tyranny (by then).

References:

Sahih al-Tirmidhi volume 2 page 86, volume 9 pages 74-75
Sunan Abu Dawud volume 2 page 7
Musnad Ahmad Ibn Hanbal volume 1 pages 84, 376; volume 3 page 63
al-Mustadrak ala al-Sahihayn by al-Hakim volume 4, page 557
Jame al-Saghir by al-Suyuti pages 2, 160
al-Urful Wardi by al-Suyuti page 2
al-Majma by al-Tabarani page 217
Tahdhib al-Tahdhib by Ibn Hajar al-Asqalani volume 9 page 144
Fat’h al-Bari fi Sharh Sahih al-Bukhari by Ibn Hajar Asqalani, volume 7 page 305
al-Sawa’iq al-Muhriqah, by Ibn Hajar al-Haythami chapter 11 section 1 page 249
al-Tazkirah, by al-Qurtubi page 617
al-Hawi by al-Suyuti volume 2 pages 165-166
Sharh al-Mawahib al-Ladunniyyah by al-Zurqani, v5, p348
Fat’h al-Mugheeth by al-Sakhawi volume 3 page 41
Kanz al-Ummal volume 7 page 186
Iqd al-Durar Fi Akhbar Mahdi al-Muntazar volume 12 chapter 1
al-Bayan Fee Akhbar Sahib al-Zaman by Yusuf Ganji Shafaei, chapter 12
al-Fusool al-Muhimmah by Ibn Sabbagh al-Maliki chapter 12
Arjahul Matalib by Ubaidallah Hindi al-Hanafi page 380
Muqaddimah by Ibn Khaldoon page 266
and also in the works of Ibn Habban, Abu Nua’ym, Ibn Asakir, etc.

Also the Holy Prophet (sawa) said, Mahdi is one of us, the members of the household (Ahle Bayt). (Sunan Ibn Majah, volume 2, tradition no. 4085)

It is evident from the above traditions that Imam Mahdi (as) is from the Ahle Bayt of Prophet Mohammed, so he can not be Hazrat Isa (as) (the Messiah). Thus, Mahdi and Messiah are two different personalities but they come at the same time, Mahdi as Imam and Jesus as his follower.

Holy Prophet (sawa) said, “If there remains nothing in this world save one night, a man from the Ahlul Bayt will rule in it.” (Mawaared-uz-Zamane Ela Zawaed Ibne Hibbaan by Hafiz Nooruddin Ali Ibne Abi Bakr, chapter 221, Maa Jaa Fi Mahdi tradition 1876)

Holy Prophet (sawa) said, “The Hour (Qiyamat) will not be established until a man from my Ahlul Bayt will rule. He will have my name and will fill the world with justice and equity as it would be filled with injustice and tyranny.” (Mawaared-uz-Zamane Ela Zawaed Ibne Hibbaan by Hafiz Nooruddin Ali Ibne Abi Bakr, chapter 221, Maa Jaa Fi Mahdi, tradition 1878)

Holy Prophet (sawa) said, “If there remains only a single day, Allah will raise a man from my Ahlul Bayt who will fill it with justice as it will be rife with injustice and oppression.” (Al Fusoolul Mohimmah Fi Marefat Ahwalul Aimmah wa Fazlohum byNooruddin Ali Ibne Mohd Ibne Ahmed Al Maroof)

Holy Prophet (sawa) said, “Mahdi is from my Ahlul Bayt. Allah will set his affairs right within one night.” (Al Haawi lil Faqawi by Jalaluddin Abdur Rahman bin Abi Bakr bin Mohd Suyuti volume 2).

Holy Prophet (sawa) said, “Mahdi is from my Ahlul Bayt.” (Al Qawlul Mukhtasar Fi Alamaatil Mahdi Muntazar by Abul Abbas Ahmad ibne Mohd Ibne Hajar Makki).

Holy Prophet (sawa) said, “Mahdi is from my Ahlul Bayt” (Al Isha’atel Ishratus Sa’aa by Mohammed ibne Abdur Rasul ibne Abdus Sayyed Hasaniush Shafaee)

Holy Prophet (sawa) said, “This world will not end until a man will rule over Arabs from my Ahlul Bayt whose name will be similar to that of my name.” (Yanabiul Mawaddah by Hafiz Sulayman ibn Ibrahim Qunduzi Hanafi, page 89, chapter Babus Saalis Wa Saabun).

Holy Prophet (sawa) said, “O Fatemah! Our prophet is the best of all prophets and he is your father; our martyrs are the best of all martyrs and he is uncle of your father – Hamza; and from us is the one who has two wings with which he flies anywhere in paradise and he is the son of your uncle – Jafar; and from us are the chiefs of this Ummat – Hasan and Husain and your sons and from us is the Mahdi.” (Al Bayan Fi Akhbare Sahebuz Zaman, page 98, chapter 2 – Mahdi is from the Progeny of Fatemah) (Sunan Ibne Majah, chapter 34, Bab-ul Khurujul Mahdi, tradition 4085).

Holy Prophet (sawa) said, “The Hour will not be established until the world is full of injustice and tyranny. Then a man will reappear from my Ahlul Bayt who will fill the world with equity and justice as it will be filled with tyranny and enmity.” (Mustadrak Ala Sahihain by Al Imam Al Hafiz Abi Abdullah Al Hakim Nisaburi)

Holy Prophet (sawa) said, “Al Mahdi is from my Ahlul Bayt. He has a broad forehead, protracted nose. He will the earth with equity and justice as it will be filled with injustice and oppression.” (Mustadrak Ala Sahihain by Al Imam Al Hafiz Abi Abdullah Al Hakim Nisaburi)

Read more about Imam Mahdi in the Ahle Sunnah