MUJADDIDS IN ISLAM :
Hadrat Shah Wali-Allah ad-Dahlawi(Rah), who was the Mujaddid (Islamic Renovator) of his age (d.1176.AH.Delhi) ,wrote about Ahlu Sunnah scholars:
"Rasulullah (Sallallahu 'alaihi 'wa-sallam) said, 'Great scholars will come in Iran.' Besides great hadith scholars such as al-Bukhari, Muslim, at-Tirmidhi, Abu Dawud, an-Nasai, Ibn Maja, ad-Darimi, ad-Dara-Qutni, Hakim, al-Baihaki and many others who were educated in Iran, there are the great fiqh scholars such as Abu 't-Tayyib [Qadi Tahir at-Tabari], Shaikh Abu Hamid [al-Isfaraini], Shaikh Abu Ishaq ash-Shirazi, and al-Juwaini ['Abdullah ibn Yusuf and his son], Imam al-Haramain 'Abd al-Malik ibn 'Abdullah al-Juwaini and Imam Muhammad al-Ghazali and many many others, who were also educated in Iran. Even Imam Abu Hanifa and his disciples in Mawara an-nahr and Khurasan are the scholars of Iran and are the subject of the good news in the Hadith.
A hadith declares, 'There will come a mujaddid in every hundred years.' As he declared, a mujaddid came in each century and strengthened the religion. In the first century of the Hegira, 'Umar ibn 'Abd al-Aziz removed the cruelty of the rulers and established the principles of justice. In the second century, al-Imam ash-Shafi'i explained the knowledge of iman and separated the knowledge of fiqh. In the third century, Abu 'l-Hasan al-Ashari formulated the Ahl-as-Sunnat knowledge and rebutted the people of bidat. In the fourth century, Hakim and al-Baihaki and the like established the fundamentals of the knowledge of the Hadith, and Abu Hamid and the like spread the knowledge of fiqh. In the fifth century, Imam al-Ghazali opened a new way and said fiqh, tasawwuf and kalam were not different from one another. In the sixth century, Imam Fakhr ad-din ar-Razi spread the knowledge of kalam; and Imam an-Nawawi spread the knowledge of fiqh. Thus, a mujaddid, coming in each
century up to our time, strengthened the religion. We should not dismiss the matter by just saying that the above hadith and the like are the miracles predicting future happenings. We should also realize the importance and the value of the predicted happenings."
[Shah Wali-Allah ad-Dahlawi, Izalat al-Khafa 'an khilafati'l-Khulafa'. v II. p. 377, Karachi, 1372.]
http://www.hizmetboo...slam/ref-44.htm
ان الله تعالى يبعث لهذه الامة على رأس كلّ مائة سنة من يجدد لها دينها
Verily Allah will send at the beginning of every century such a person for this Ummah who will rejuvenate and restore their religion (Deen).
"My Shaykh said that there is a consensus of the Hadith Masters that this Hadith is Sahih."
اتفق الحفاظ على تصحيحه
It is a consensus of the Muhadditheen (Hadith Masters) that this Hadith is Sahih.
"In other words, to revive the Deen is to revive those teachings of the Quran and Sunnah that are being destroyed and to give command according to the Quran and Sunnah."
"A Mujaddid is one who separates Sunnah from Bid'ah and one who degrades the status of the Ahle Bid'ah."
Why does a Mujaddid come after 100 years?
A Mujaddid is sent after every 100 years because after every century the surroundings, the environment, the manner of thinking and ways of the people tend to pass through a massive transformation. It has been stated in the Hadith of Bukhari Shareef that during the latter stages of the Prophet's (Sallallahu Alaihi wa Sallam) physical life, one night, after performing Esha Salaah, he stood up and said,
"Should I inform you of the importance of this night? From this night onwards, right up to the end of a 100 years, that person who is alive on the earth (presently) will not be alive."