"Do not judge according to appearance, but judge with righteous judgment.” John 7:24
It is kind of a running joke in my family that when someone makes a goofy mistake, there comes a loud and defensive, albeit joking, "Don't judge me!" by the perpetrator. The reply, invented by the youngest of the kids is, "It's too late. You've already been judged."
In Christianity, we advocate the avoidance of judging others and cite scriptures like Matt 7:1-2 but then we do it anyway. Jesus addressed this contradiction by referencing the fact that there were those who wanted to kill him for miraculously healing someone on the Sabbath, a day on which no work was to be done. He pointed out that they circumcised babies on the Sabbath when the 8th day after birth fell on that day in order to keep the law but they wanted to destroy him for obeying God's ultimate law of love.
Beloved, it is not that we should not judge, but how we judge, be it favorably or unfavorably. When Jesus said, "Do not judge so that you will not be judged" in Matt 7:21, he was cautioning against having an attitude that results in unjustly looking upon the character of another and making rash and unloving judgments about them. To be sure, we must take a stand for righteousness and be able to correct our brothers and sisters when it is needed (Prov 27:6, Gal 6:1-2); however, we must consider the spirit in which this is done. Do we jump to uninformed and mean spirited conclusions based on what we see on the surface, or worse, what we have heard from others or do we apply love to the situation and treat others as we would want to be treated?
When Jesus healed despite the Sabbath, the rules of which had been extended far beyond what God stipulated by man, he did so out of love for someone who was hurting. His adversaries were upset and accused him of having a demon, being a blasphemer and many other things. This was done out of hatred, using the letter of the law rather than the spirit of the law to persecute him. Worse, it was the law that they set aside or reinterpreted when it was convenient to do so, often for much less noble reasons. Everything about this type of judgmental behavior is to be avoided. Jesus has said that when we do that to others, the same will be done to us.