رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 169
The Book of Miscellany
Prohibition of heresies in religion
عَنْ عَائِشَةَ، رَضِيَ اللَّه عَنْهَا، قَالَتْ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ: "مَنْ أَحْدَثَ فِي أَمْرِنَا هَذَا مَا لَيْسَ مِنْهُ فَهُوَ رَدٌّ" (( مُتَّفَقٌ عَلَيْهِ)). وَفِي رِوَايَةٍ لِمُسْلِمٍ : "مِنَ عَمِلَ عَمَلاً لَيْسَ عَلَيْهِ أَمْرُنَا فَهُوَ رَدٌّ".
'Aishah (May Allah be pleased with her) reported: Messenger of Allah (ﷺ) said, "If anyone introduces in our matter something which does not belong to it, will be rejected". [Al-Bukhari and Muslim]. The narration in Muslim says: "If anybody introduces a practice which is not authenticated by me, it is to be rejected".
Riyad as-Salihin, 169