The Gravity of (Telling) a Lie against Allah's Messenger صلى الله عليه وسلم

بسم الله الرحمن الرحيم ( bismi-llāhi r-raḥmāni r-raḥīm ) 

In the name of  Allah, The Most Gracious, The Most Merciful

Hadith No 2.

Narrated Anas (Razi Allah tala anhu) : The Fact which stops me from narrating a great number of Ahadith to you is that the Prophet  صلى الله عليه وسلم said, "Whoever tells a lie against me intentionally, then (surely) let him occupy his seat in Hell-fire."

(Sahîh Al-Bukhâri, Hadîth No. 108, Vol. 1)