Musnad Ahmad Hadith 22058

It is narrated from Anas (may Allah be pleased with him): Once we went to Mu'adh (may Allah be pleased with him) and said to him, "Tell us some amazing incident of the Prophet (peace and blessings of Allah be upon him)." He said, "Alright. Once I was riding behind the Prophet (peace and blessings of Allah be upon him) on a donkey. The Prophet (peace and blessings of Allah be upon him) called me by name and said, 'O Mu'adh!' I replied, 'At your service, O Messenger of Allah!' The Prophet (peace and blessings of Allah be upon him) said, 'Do you know what right Allah has over His servants?' I replied, 'Allah and His Messenger know best.' The Prophet (peace and blessings of Allah be upon him) said, '(Allah's right over His servants is) that they worship Him alone and do not associate anything with Him.' Then the Prophet (peace and blessings of Allah be upon him) said, 'Do you know what right the servants have over Allah if they do that?' The Prophet (peace and blessings of Allah be upon him) said, 'Their right is that Allah will not punish them.'"