The Messenger (sallal-laahu-alayhi-wasallam) said: ”Whoever tells lies about me intentionally then let him take his place in hell.’’

Al-Haafidh Ibn Hajar (rahimahullaah) said: The wisdom behind the severity of telling lies against the Prophet (sallal-laahu-alayhi-wasallam) is clear, for indeed he transmits information from Allaah (The Most High).  So whoever lies against him has lied against Allaah….

[For further details see:  Dawaabit Ar-Riwaayah Indal Muhadditheen Vol 1 page 134 by Shaikh Raslaan (may Allaah preserve him)]