Sahih al-Bukhari 108
Sahih al-Bukhari · Book 3: Knowledge · The sin of a person who tells a lie against the Prophet (saws)
Narrated Anas:
حَدَّثَنَا أَبُو مَعْمَرٍ ، قَالَ حَدَّثَنَا عَبْدُ الْوَارِثِ ، عَنْ عَبْدِ الْعَزِيزِ ، قَالَ أَنَسٌ إِنَّهُ لَيَمْنَعُنِي أَنْ أُحَدِّثَكُمْ حَدِيثًا كَثِيرًا أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " مَنْ تَعَمَّدَ عَلَىَّ كَذِبًا فَلْيَتَبَوَّأْ مَقْعَدَهُ مِنَ النَّارِ " .
The fact which stops me from narrating a great number of Hadiths to you is that the Prophet (ﷺ) said: "Whoever tells a lie against me intentionally, then (surely) let him occupy his seat in Hell-fire."