The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship
Ṣaḥīḥ Muslim 6525
لَئِنْ كُنْتَ كَمَا قُلْتَ فَكَأَنَّمَا تُسِفُّهُمُ الْمَلَّ وَلاَ يَزَالُ مَعَكَ مِنَ اللَّهِ ظَهِيرٌ عَلَيْهِمْ مَا دُمْتَ عَلَى ذَلِكَ
laʾin kunta kamā qulta fakaʾannamā tusiffuhumu al-malla walā yazālu maʿaka mina-Llāh ẓahīrun ʿalayhim mā dumta ʿalā dhalika
Transliteration generated from the Arabic vowel marks
The full narration
Abu Huraira reported that a person said:Allah's Messenger, I have relatives with whom I try, to have close relationship, but they sever (this relation). I treat them well, but they treat me ill. I am sweet to them but they are harsh towards me. Upon this he (the Holy Prophet) said: If it is so as you say, then you in fact throw hot ashes (upon their faces) and there would always remain with you on behalf of Allah (an Angel to support you) who would keep you dominant over them so long as you adhere to this (path of righteousness)
Source
Ṣaḥīḥ Muslim · 6525