The wicked man craves evil; his neighbor gets no mercy from him. Proverbs 21:10
Have you ever wondered why some people seem not to have a conscience? Take the ruthless dictators that have populated the earth: Idi Amin, Saddam Hussein, Adolph Hitler, Pol Pot, and even some who live today. The power they so crave drives them to commit unimaginable sins. The people under them become like them and are less and less prone to give up their control of people.
The more evil that a person commits, the less likely that their conscience will affect that person, and the more likely that that person will commit even greater atrocities.
Today there are a few countries around the world where this is true. Syria is one; Cuba is another. Pray for these two nations. Pray that the Believers there will be bold and courageous in the midst of the evil they see around them.