Hadithcore
Al-Adab Al-Mufrad, 321
sahih· Al-Albani

Abu Hurayra said, "The Messenger of Allah, (ﷺ), was asked, "Messenger of Allah, invoke a curse for us against the idolaters.' He replied, 'I was not sent as a curser. I was sent as a mercy.'"

حَدَّثَنَا مُحَمَّدٍ قَالَ‏:‏ عَبْدُ اللهِ بْنُ محمد قال حَدَّثَنَا مَرْوَانُ بْنُ مُعَاوِيَةَ، حَدَّثَنَا يَزِيدُ، عَنْ أَبِي حَازِمٍ، عَنْ أَبِي هُرَيْرَةَ قَالَ‏:‏ قِيلَ‏:‏ يَا رَسُولَ اللهِ، ادْعُ اللَّهَ عَلَى الْمُشْرِكِينَ، قَالَ‏:‏ إِنِّي لَمْ أُبْعَثْ لَعَّانًا، وَلَكِنْ بُعِثْتُ رَحْمَةً‏.‏

References2 variants
In-Book Reference
Book 15, Hadith 13
English Reference
Book 15, Hadith 321