He also told them a parable: “Can a blind man lead a blind man? Will they not both fall into a pit? A disciple is not above his teacher, but everyone when he is fully trained will be like his teacher. Why do you see the speck that is in your brother's eye, but do not notice the log that is in your own eye? How can you say to your brother, ‘Brother, let me take out the speck that is in your eye,’ when you yourself do not see the log that is in your own eye? You hypocrite, first take the log out of your own eye, and then you will see clearly to take out the speck that is in your brother's eye.
People are judgmental by nature. We judge people's behavior. We make snap judgments based on first impressions. We form opinions about situations without knowing the facts. And if you are sitting there thinking that you don't judge people, I bet you are judging all these judgmental people!
We can be remarkably alert to the failings of others while blind to our own shortcomings. Often the things for which we judge others or which annoy us about others are the very logs jabbing into our own eyes. (For example, I abhored procrastination and talking in class when I was a teacher. But just ask my mom what comments she received about me when I was in school!) Or perhaps we are acutely aware that there is a log in our eye, but we hope that pointing out the sawdust in someone else's eye will work some misdirection and keep everyone from pointing at our sinfulness. And we can do it with such kindness, "Oh please can I help you with that speck my brother?"
Does this mean we should never point out the faults of others? Matthew 18:15-20 gives a model for how to confront believers who sin against us. But following the previous passage it would seem that in most cases it is probably wise to "turn the other cheek" and focus on addressing our own sins. I have children who are 3 and 6. Usually they play well together, but when they are reprimanded for fighting you can imagine their first word: "But he..." and "But she..." Mommy and Daddy are quick to remind them to worry about their own behavior, not the other person's. Adults are just as quick to focus on the fault of the other party without contemplating our own role in any discord. Only after searching our own souls and confessing our own sin should we even consider trying to "take out the speck" from our brother's eye.
If we do not judge, do not condemn, and always give and forgive does that mean we will always be blessed and treated fairly? Of course not. God may not give you physical comfort and the favor of others in this life. But as we live in His will and become more like Christ we experience more of God's overflowing favor in our lives. The mercy we receive for our transgressions against God is far greater than any we extend to others.
Therefore you have no excuse, everyone of you who passes judgment, for in that which you judge another, you condemn yourself; for you who judge practice the same things. And we know that the judgment of God rightly falls upon those who practice such things. But do you suppose this, O man, when you pass judgment on those who practice such things and do the same yourself, that you will escape the judgment of God? Or do you think lightly of the riches of His kindness and tolerance and patience, not knowing that the kindness of God leads you to repentance? But because of your stubbornness and unrepentant heart you are storing up wrath for yourself in the day of wrath and revelation of the righteous judgment of God, for He will render to each one according to his works. - Romans 2:1-7