George Orwell 1984 pg.16

Quote:
War is peace, freedom is slavery, and ignorance is strength.

What it means:
War is peace means that if your at war in the opponents territory its less likely that they will attack your cities. It also means if you destroy your enemies they cant hurt you anymore. Freedom is slavery means when you're free you're a slave to competition. Ignorance is strength means if you don't believe the government is lying to you then they aren't in your own world.

Apply it:
The government in the book 1984 was using these three sayings to try to keep order among the people. These sayings are designed to make you think that the government is good. War is peace makes them not question if they should be at war, freedom is slavery makes them not want to rebel, and ignorance is strength makes them believe in their government.