"Judge Not, lest ye be judged" is from the book of Matthew in the bible, taken from the King James version.
We have no right to judge others because it is not our place to begin with. What other people do is thier own business and whether it is right or wrong is not for us to decide. God is the only person who should and WILL judge others. Until that time, we need to not be concerned with others and make sure we living a morally just life.