كتاب العلم
47  
The Book of Knowledge
(6)
Chapter: The One Who Starts Something Good Or Something Bad; The One Who Calls Others To Guidance Or Misguidance
(6)
باب مَنْ سَنَّ سُنَّةً حَسَنَةً أَوْ سَيِّئَةً وَمَنْ دَعَا إِلَى هُدًى أَوْ ضَلاَلَةٍ
Sahih Muslim 2674

Abu Huraira reported Allah's Messenger (ﷺ) as saying:

He who called (people) to righteousness, there would be reward (assured) for him like the rewards of those who adhered to it, without their rewards being diminished in any respect. And he who called (people) to error, he shall have to carry (the burden) of its sin, like those who committed it, without their sins being diminished in any respect.
حَدَّثَنَا يَحْيَى بْنُ أَيُّوبَ، وَقُتَيْبَةُ بْنُ سَعِيدٍ، وَابْنُ، حُجْرٍ قَالُوا حَدَّثَنَا إِسْمَاعِيلُ، - يَعْنُونَ ابْنَ جَعْفَرٍ - عَنِ الْعَلاَءِ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ مَنْ دَعَا إِلَى هُدًى كَانَ لَهُ مِنَ الأَجْرِ مِثْلُ أُجُورِ مَنْ تَبِعَهُ لاَ يَنْقُصُ ذَلِكَ مِنْ أُجُورِهِمْ شَيْئًا وَمَنْ دَعَا إِلَى ضَلاَلَةٍ كَانَ عَلَيْهِ مِنَ الإِثْمِ مِثْلُ آثَامِ مَنْ تَبِعَهُ لاَ يَنْقُصُ ذَلِكَ مِنْ آثَامِهِمْ شَيْئًا ‏"‏ ‏.‏
Reference : Sahih Muslim 2674
In-book reference : Book 47, Hadith 30
USC-MSA web (English) reference : Book 34, Hadith 6470
  (deprecated numbering scheme)