Hadith 181
Tamim bin Aus Ad-Dari (May Allah be pleased with him) reported:
فالأول: عن أبي رقية تميم بن أوس الداري رضي الله عنه أن النبي صلى الله عليه وسلم قال: " الدين النصيحة" قلنا: لمن؟ قال: لله ولكتابه ولرسوله ولأئمة المسلمين وعامتهم ((رواه مسلم)).
The Prophet (ﷺ) said, "Ad-Deen is sincerity". We said: "For whom?" He replied, "For Allah, His Book, His Messenger and for the leaders of the Muslims and their masses". [Muslim].
In plain words
The Prophet said the religion itself is sincere goodwill, owed to Allah, His Book, His Messenger, and to the leaders and the wider body of Muslims. Genuinely wanting good for all of these lies at the heart of faith.
Reference : Riyad as-Salihin 181 In-book reference : Introduction, Hadith 181