Mishkat al-Masabih
Mishkat al-Masabih 168, 169
وَعَنْ بِلَالِ بْنِ الْحَارِثِ الْمُزَنِيِّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسلم: «من أَحْيَا سُنَّةً مِنْ سُنَّتِي قَدْ أُمِيتَتْ بَعْدِي فَإِنَّ لَهُ مِنَ الْأَجْرِ مِثْلَ أُجُورِ مَنْ عَمِلَ بِهَا مِنْ غَيْرِ أَنْ يَنْقُصَ مِنْ أُجُورِهِمْ شَيْئًا وَمَنِ ابْتَدَعَ بِدْعَةً ضَلَالَةً لَا يَرْضَاهَا اللَّهُ وَرَسُولُهُ كَانَ عَلَيْهِ مِنَ الْإِثْمِ مِثْلُ آثَامِ مَنْ عَمِلَ بِهَا لَا يَنْقُصُ من أوزارهم شَيْئا» . رَوَاهُ التِّرْمِذِيّ وَرَوَاهُ ابْنُ مَاجَهْ عَنْ كَثِيرِ بْنِ عَبْدِ اللَّهِ بْنِ عَمْرٍو عَنْ أَبِيهِ عَنْ جَدِّهِ
Bilāl ibn al-Ḥārith al-Muzanī reported that the Messenger of God said: ‘Whoever revives one of my Sunnahs that was abandoned after me will have a reward equal to the rewards of those who act upon it, without their rewards being diminished at all. Whoever introduces a misguiding innovation that God and His Messenger do not approve of will bear a sin equal to the sins of those who act upon it, without their burdens being diminished at all.’ Al-Tirmidhi transmitted it. Ibn Mājah also transmitted it from Kathīr ibn ʿAbd Allah ibn ʿAmr, from his father, from his grandfather.