Research on the understanding of congratulating non-Muslim religious holidays is one of the contemporary fiqh issues that continues to be debated among scholars. Differences of views arise because of differences in understanding the concept of tolerance (tasāmuḥ), religious loyalty (al-walā' wa al-barā'), and social relations between religious people (mu'āmalah). Some scholars prohibit the giving of congratulations because they are considered to have the potential to contain recognition of the teachings and beliefs of other religions, while other scholars allow as long as they do not contain justifications for non-Muslim beliefs and are only intended as a form of social respect and an effort to maintain harmony in community life. This study aims to analyze the law of congratulating on non-Muslim religious holidays based on the postulates of the Qur'an, the hadith of the Prophet, as well as the views of classical and contemporary scholars. The research uses a qualitative approach with the type of library research and normative analysis methods. Data was obtained from primary sources in the form of the Qur'an, hadith, fiqh books, and works of contemporary scholars who discuss the relationship between religious communities. The results of the study show that the difference in law is rooted in the difference in interpretation of the nash and the rules of fiqh used. The view that prohibits is based on the principle of maintaining the purity of the faith and the prohibition resembles non-Muslim religious practices, while the view that allows emphasizes aspects of social welfare, the principle of justice, and the importance of building harmonious relations without sacrificing the Islamic faith. Thus, congratulations can be understood as a form of social interaction that is permissible as long as it is not accompanied by recognition of the theological truths of other religions or participation in their religious rituals. From a da'wah perspective, the findings position respectful interreligious communication as contextual da'wah that preserves Islamic creed while promoting social harmony. The study therefore recommends a wisdom-based da'wah approach that communicates juristic differences proportionally and prevents religious messages from intensifying social polarization.