Sahih Muslim Book - 1, Hadith - 144

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ حَدَّثَنَا أَبُو الْأَحْوَصِ سَلَّامُ بْنُ سُلَيْمٍ عَنْ أَبِي إِسْحَاقَ عَنْ عَمْرِو بْنِ مَيْمُونٍ عَنْ مُعَاذِ بْنِ جَبَلٍ قَالَ كُنْتُ رِدْفَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى حِمَارٍ يُقَالُ لَهُ عُفَيْرٌ قَالَ فَقَالَ يَا مُعَاذُ! أَتَدْرِي مَا حَقُّ اللَّهِ عَلَى الْعِبَادِ وَمَا حَقُّ الْعِبَادِ عَلَى اللَّهِ؟ قَالَ قُلْتُ اللَّهُ وَرَسُولُهُ أَعْلَمُ قَالَ فَإِنَّ حَقَّ اللَّهِ عَلَى الْعِبَادِ أَنْ يَعْبُدُوا اللَّهَ وَلَا يُشْرِكُوا بِهِ شَيْئًا وَحَقُّ الْعِبَادِ عَلَى اللَّهِ عَزَّ وَجَلَّ أَنْ لَا يُعَذِّبَ مَنْ لَا يُشْرِكُ بِهِ [شَيْئًا] قَالَ قُلْتُ يَا رَسُولَ اللَّهِ أَفَلَا أُبَشِّرُ النَّاسَ؟ قَالَ لَا تُبَشِّرْهُمْ فَيَتَّكِلُوا.

It was narrated that Mu'adh bin Jabal said: "I was riding behind the Messenger of Allah (s.a.w) on a donkey called 'Ufair, and he said: 'O Mu'adh, do you know what is the right of Allah over (His) slaves and the right of (His) slaves over Allah?' I said: 'Allah and His Messenger know best.' He said: 'The right of Allah over (His) slaves is that they should worship Allah and not associate anything with Him, and the right of (His) slaves over Allah [the Mighty and Sublime,] is that He should not punish the one who does not associate anything with Him.' I said: 'O Messenger of Allah, should I not tell the people of this good news?' He said: 'Do not tell them, lest they (complacently) rely on it.'"