Abu Huraira told that when God's messenger was asked to invoke a curse on the polytheists, he replied, "I was not sent as one given to cursing; I was sent only as a mercy." Muslim transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب الفضائل والشمائل / 5812
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه مسلم (87/ 2599)»