Judging is a very sensitive issue in our present world. As Christians, we are to judge sin and love the sinner. We are all sinners.
In the midst of being sinners, we believe in Jesus. Therefore in the midst of being sinners, we as Christians have to help each other to holiness.
If we judge people, by their actions then God will judge us by our actions, which could be a terrifying thought.
But, if we judge the sin and love the person, then we can help them identify the wrong and improve their life in holiness. This means we also have to accept the constructive correction from others.
Imagine if we truly lived this way we would help each other be the best Christians ever, and truly make His Kingdom come on earth as in Heaven.