Jami` at-Tirmidhi, Volume 4, Book 25, Hadith 2026 (DarusSalam) ⓘ
Hammam bin Al-Harith said: "Aman passed by Hudhaifah bin Al-Yaman and it was said to him: "This person conveys news about the people to the leaders.' So Hudaifah said: 'The Messenger of Allah said: 'The Qatat shall not enter paradise.'" (Sahih)Sufyan said: "The Qatat is the Nammam.
حَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ مَنْصُورٍ، عَنْ إِبْرَاهِيمَ، عَنْ هَمَّامِ بْنِ الْحَارِثِ، قَالَ مَرَّ رَجُلٌ عَلَى حُذَيْفَةَ بْنِ الْيَمَانِ فَقِيلَ لَهُ إِنَّ هَذَا يُبَلِّغُ الأُمَرَاءَ الْحَدِيثَ عَنِ النَّاسِ . فَقَالَ حُذَيْفَةُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " لاَ يَدْخُلُ الْجَنَّةَ قَتَّاتٌ " . قَالَ سُفْيَانُ وَالْقَتَّاتُ النَّمَّامُ . وَهَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
also referenced under: Hadith 2026 (Reference) & Book 27, Hadith 132 (In-Book)