From Abū Ruqayyah Tamīm bin Aws al-Dārī (raḍiyallāhu ʿanhum) who said that the Prophet (ﷺ) said:
“The religion is sincerity of purpose.” We said, “To whom?” He said, “To Allāh, His
Book, His Messenger, the leaders of
the Muslims and their general folk.” (Related by Muslim)
Translation source: AlhudaBolton.com