The attraction in the study of religion continues to develop in this era of globalization. Muslim scholars have pioneered the effort and signinifantly contributed works and achiements in the study of religion. Thus, this study aims to highilight the achievements of Rahmatullah Al-Kairanawi, a 19th century Muslim scholar who specialised in the study of religion. Exposure to contemporary and future researchers on the great treatises of Muslim heritage in study of religion is significance of this study. This study uses qualitative methods through content analysis of the previous research, books, papers and previous thesis related to Rahmatullah Al-Kairanawi. The study found that Rahmatullah Al-Kairanawi made the important contributions in strengthening and defending the Islamic faith from external threats such as extreme non-Muslims, in the 19th century. Keywords: history of religion, comparative religion, izhar al-haq, rahmatullah al-kairanawi.

To emphasise the approach in the study of religion, this study compares Ninian Smart and Rahmatullah Al-Kairanawi, two intellectuals from the Western and Muslim civilizations in the 19th century. It examines the different perspectives of both experts on religion with the objective of identifying similarities and differences in their methods to religion study. The qualitative method is used to gather and analyse data from these expert' scholarly publications.The conclusion is that in the study of religions, Ninian Smart and Rahmatullah Al-Kairanawi have different perspectives and methodologies. According to the findings of this study, both experts are concerned about data integrity and intellectual honesty. Their methods can be used to better comprehend religious dialogue and engagement, as well as to contribute to the global peace process.