Hadith #194
Arabic Text
وَبِإِسْنَادِهِ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الْمَدِينَةُ مَنْ أَحْدَثَ فِيهَا حَدَثًا أَوْ آوَى مُحْدِثًا أَوْ تَوَلَّى غَيْرَ مَوْلَاهُ فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلَائِكَةِ وَالنَّاسِ أَجْمَعِينَ لَا يَقْبَلُ اللَّهُ مِنْهُ صَرْفًا وَلَا عَدْلًا
English Translation
With the same chain of narration, he said: the Messenger of Allah ﷺ said: "Madinah — whoever introduces a heretical innovation in it, or shelters an innovator, or claims allegiance to other than his rightful patron, upon him is the curse of Allah, the angels, and all of mankind. Allah will accept from him neither obligatory nor voluntary deeds."
Quran References
Reference: Musnad Ahmad, Book 21, Hadith 194
Sunnah.com ref: Musnad Ahmad 9432
Islam.wiki ID: IWH-45822