Jesus told his disciples to judge righteous judgment(John 7:24). In the minds of some these words supersede what Jesus said elsewhere about not judging (Matthew 7:1). What is righteous judgment? What does it involve?
To some, righteous judgment involves no more than knowing what the rules are, interpreting then correctly, and applying them rigorously. I'd suggest that there is much, much more to any judgment which rises to the standard of righteousness. In fact, such judgment would require omniscience, perfect knowledge of all the circumstances surrounding the item or person under judgment.
When Jesus appended the word righteous (correct, proper, unprejudiced in anyway) to the word judgment, he removed judgment from the realm of possibility as far as humans are concerned. These words do not negate the command to judge not. Instead they clarify why judgment and any associated retribution is not the work and responsibility of men
We can aspire to righteousness for ourselves, but we cannot impose righteousness on others. Our personal example is all that we need to encourage righteousness.