Sunan Ibn Majah 204
It was narrated that Abu Hurairah said:
"A man came to the Prophet, who encouraged the people to give charity to him. A man said: 'I have such and such,' and there was no one left in that gathering who did not give him something in charity, to a greater or lesser extent. The Messenger of Allah said: 'Whoever initiates a good practice that is followed, he will receive a perfect reward for that, and a reward equivalent to that of those who follow it, without that detracting from their reward in the slightest. And whoever introduces a bad practice that is followed, he will receive the complete burden of sin for that, and a burden of sin equivalent to that of those who follow it without that detracting from their burden in the slightest.'"
حَدَّثَنَا عَبْدُ الْوَارِثِ بْنُ عَبْدِ الصَّمَدِ بْنِ عَبْدِ الْوَارِثِ، حَدَّثَنِي أَبِي، حَدَّثَنِي أَبِي، عَنْ أَيُّوبَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ جَاءَ رَجُلٌ إِلَى النَّبِيِّ ـ صلى الله عليه وسلم ـ فَحَثَّ عَلَيْهِ فَقَالَ رَجُلٌ عِنْدِي كَذَا وَكَذَا ‏.‏ قَالَ فَمَا بَقِيَ فِي الْمَجْلِسِ رَجُلٌ إِلاَّ تَصَدَّقَ عَلَيْهِ بِمَا قَلَّ أَوْ كَثُرَ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏
"‏ مَنِ اسْتَنَّ خَيْرًا فَاسْتُنَّ بِهِ كَانَ لَهُ أَجْرُهُ كَامِلاً وَمِنْ أُجُورِ مَنِ اسْتَنَّ بِهِ وَلاَ يَنْقُصُ مِنْ أُجُورِهِمْ شَيْئًا وَمَنِ اسْتَنَّ سُنَّةً سَيِّئَةً فَاسْتُنَّ بِهِ فَعَلَيْهِ وِزْرُهُ كَامِلاً وَمِنْ أَوْزَارِ الَّذِينَ اسْتَنَّ بِهِ وَلاَ يَنْقُصُ مِنْ أَوْزَارِهِمْ شَيْئًا ‏"‏ ‏.‏