Questioner: There is an authentic hadith which states that at the start of every hundred years [Allaah will raise someone] who will revive this Ummah’s religion for it, is it a condition that these revivers [Mujaddids] be from Ahlus-Sunnah or not?
Al-Albaani: No doubt. It is a fundamental condition and this is the reality that I hold [to be the case]. In my opinion, this question is like if someone were to ask–and I hope that such a question does not actually emanate from a questioner—it’s like if someone were to ask, ‘Is it a condition that he be a Muslim?’ Naturally, such a question will not be asked, ‘Is it a condition that a reviver [mujaddid] be a Muslim?’ I think this will never occur to someone [to ask].
As for whether it is a condition that he be from Ahlus-Sunnah, then such a question may occur to some people, and for this reason it was raised just now.
The answer is that he definitely has to be from Ahlus-Sunnah, and [by saying that he has to be from] Ahlus-Sunnah, I don’t mean that he has to be from the scholars … but rather that he be upon the methodology of Ahlus-Sunnah and not deviated from the path which has come to us from the Salaf as-Saalih, may Allaah be pleased with them, this is a must, but the reviver [mujaddid]—and even though this [point] is not connected to the question I still believe that there is a huge benefit in it—it is not a condition that the reviver be a reviver of the religion only, rather he can be a reviver in everything which benefits the Muslims. So he could, for example, be a reviver in history, a reviver in medicine—but within the aforementioned parameters, i.e., of being from Ahlus-Sunnah wal-Jamaa’ah.
So based upon this, in the end we can picture that during one time there can be more than one reviver, when we take this wide meaning into consideration, it is possible for me to picture, at one period, a gathering of a number of revivers, each one in his own specialist field.
Al-Hudaa wan-Noor, 313.