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A reviver is an individual who revitalizes or renews a movement or belief. In the context of Islam, Ahmed Raza Khan Barelvi is regarded as a reviver due to his significant contributions in preserving and reinvigorating Islamic practices, teachings, and literature. He played a pivotal role in propagating the Hanafi school of thought and is particularly renowned for his extensive knowledge and prolific writings in Islamic jurisprudence, theology, and spirituality.