A tradition From the Holy Prophet (saw) declares:“Beware I inform you regarding the greatest of the mortal sins: Associating anything with Allah, disobeying parents and lying!”
A similar tradition has been quoted From Imam al-Hasan al-Askari:“All the evils have been locked in a room and its key is lying.”
Lying in Islam is one of the characteristics of the hypocrites, and it is a blameworthy trait which encourages one to commit evil and prevents one From doing good.