كتاب الإيمان
1  
The Book of Faith
(45)
Chapter: Clarifying the emphatic prohibition of An-Namimah (Malicious Gossip)
(45)
باب بَيَانِ غِلَظِ تَحْرِيمِ النَّمِيمَةِ ‏‏
Sahih Muslim 105 b

It is reported on the authority of Hammam b, al-Harith that a man used to carry tales to the governor. We were sitting in the mosque. the people said:

He is one who carries tales to the governor. He (the narrator) said: Then he came and sat with us. Thereupon Hudhaifa remarked: I heard the Messenger of Allah (ﷺ) saying: The beater of false tales would never enter heaven.
حَدَّثَنَا عَلِيُّ بْنُ حُجْرٍ السَّعْدِيُّ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ إِسْحَاقُ أَخْبَرَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ إِبْرَاهِيمَ، عَنْ هَمَّامِ بْنِ الْحَارِثِ، قَالَ كَانَ رَجُلٌ يَنْقُلُ الْحَدِيثَ إِلَى الأَمِيرِ فَكُنَّا جُلُوسًا فِي الْمَسْجِدِ فَقَالَ الْقَوْمُ هَذَا مِمَّنْ يَنْقُلُ الْحَدِيثَ إِلَى الأَمِيرِ ‏.‏ قَالَ فَجَاءَ حَتَّى جَلَسَ إِلَيْنَا ‏.‏ فَقَالَ حُذَيْفَةُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ لاَ يَدْخُلُ الْجَنَّةَ قَتَّاتٌ ‏"‏ ‏.‏
Reference : Sahih Muslim 105b
In-book reference : Book 1, Hadith 197
USC-MSA web (English) reference : Book 1, Hadith 190
  (deprecated numbering scheme)