What did Prophet Muhammad (peace be upon him) say were Allah's rights upon His slaves and what was the right of slaves on Allah if they upheld it?
 Narrated Mu`adh:                     While I was a companion rider with the Prophet he said, "O Mu`adh!" I replied, "Labbaik wa Sa`daik." He repeated this call three times and then said, "Do you know what Allah's Right on His slaves is?" I replied, "No." He said, Allah's Right on His slaves is that they should worship Him (Alone) and should not join partners in worship with Him." He said, "O Mu`adh!" I replied, "Labbaik wa Sa`daik." He said, "Do you know what the right of (Allah's) salves on Allah is, if they do that (worship Him Alone and join none in His worship)? It is that He will not punish them."