people who live in glass houses shouldnt throw stones

People who live in glass houses shouldnt throw stones is another way to say that you should not criticize other people for having the same type of faults that you have yourself. By speaking of throwing stones at other houses when you have a glass house shows to mean that those stones can therefore come back at you and break your glass house. It is a lesson for people to not be hypocrites and judge others based on something that is true of yourself.