Mishkat al-Masabih, hadith 22

وَعَن معَاذ رَضِي الله عَنهُ قَالَ كُنْتُ رِدْفَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسلم على حمَار يُقَال لَهُ عفير فَقَالَ يَا معَاذ هَل تَدْرِي حَقُّ اللَّهِ عَلَى عِبَادِهِ وَمَا حَقُّ الْعِبَادِ عَلَى اللَّهِ؟ قُلْتُ اللَّهُ وَرَسُولُهُ أَعْلَمُ قَالَ فَإِنَّ حَقَّ اللَّهِ عَلَى الْعِبَادِ أَنْ يَعْبُدُوهُ وَلَا يُشْرِكُوا بِهِ شَيْئًا وَحَقُّ الْعِبَادِ عَلَى اللَّهِ أَنْ لَا يُعَذِّبَ مَنْ لَا يُشْرِكُ بِهِ شَيْئًا فَقُلْتُ يَا رَسُولَ اللَّهِ أَفَلَا أُبَشِّرُ بِهِ النَّاسَ قَالَ لَا تُبَشِّرُهُمْ فَيَتَّكِلُوا

I was riding behind the Prophet on an ass with nothing between him and me but the rear part of the saddle, when he said, “Do you know, Mu'adh, what God has a right to expect from His servants, and what His servants have a right to expect from God?” I replied, “God and His messenger know best.” He said, “What God has a right to expect from His servants is that they should worship Him, not associating anything with him; and what the servants have a right to expect from God is that He should not punish one who does not associate anything with Him.” I said, “Messenger of God, shall I not give this good news to the people?” He replied, “Do not tell them, and have them trusting in it alone.” (Bukhari and Muslim.)