(1) باب مَا جَاءَ فِي دُعَاءِ النَّبِيِّ صلى الله عليه وسلم أُمَّتَهُ إِلَى تَوْحِيدِ اللَّهِ تَبَارَكَ وَتَعَلَى
Narrated Mu`adh bin Jabal:
The Prophet (ﷺ) said, "O Mu`adh! Do you know what Allah's Right upon His slaves is?" I said, "Allah and His Apostle know best." The Prophet (ﷺ) said, "To worship Him (Allah) Alone and to join none in worship with Him (Allah). Do you know what their right upon Him is?" I replied, "Allah and His Apostle know best." The Prophet (ﷺ) said, "Not to punish them (if they do so).
Reference: Sahih al-Bukhari 7373
In-book reference: Book 97, Hadith 3
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 93, Hadith 470