Forging lies against Allah, the Messenger and the Religious Authorities is forbidden in religion.
Allah the Most High said: “And who is more unjust than he who forges a lie against Allah.”
He also said: “Surely those who forge lies against Allah shall not prosper. They will have little enjoyment for a while, but theirs will be a painful punishment.”
The Holy Prophet Muhammad (S) said: “Any one who intentionally forges lies against me prepares for a residence of fire.”
Imam Ja’far al-Sadiq (a.s.) said: “The forging of lies against religious authorities is like the forging of lies against the Messenger of Allah; and the forging of lies against the Messenger of Allah is like the forging of lies against Allah; and he who forges lies against Allah will he punished by the Most High Allah.”
He (a.s.) also said: “Forging lies against Allah, His Messenger and the later’s successors is a grave (mortal) sin.”