* The false swearer and the perjurer do badly to themselves by exposing them to the wrath of God.
* The false swearer and the perjurer do badly to those who encourage them to swear falsely, because such persons support in the fields of wronging people’s rights and insulting their dignities.
* The false swearer and the perjurer do badly to those against whom they swear falsely because they deprive them of their rights.
* The false swearer and the perjurer do badly to the community as a whole, because they spread disorder and destroy the religious and moral values.
* The false swearer and the perjurer do badly to the Islamic Sharia, because they challenge its sacred constitution.
source : http://www.maaref-foundation.com