Why not judge others?

1 “Do not judge, or you too will be judged.  
We are to judge actions but not motives.  We judge the what and not the why.  The Bible judges many actions: murder, adultery, theft.  But the person was created in the image of God and only God is all-wise and all-knowing enough to truly know why someone did something.

2 For in the same way you judge others, you will be judged, and with the measure you use, it will be measured to you.  
When you judge someone what you are really saying is that if you were in that person's circumstances and you did what they did you would be thinking a certain evil.  This would be based on the fact that you had a similar experience in the past.  And so the measure you use for them is the measure you gave yourself.

3 “Why do you look at the speck of sawdust in your brother’s eye and pay no attention to the plank in your own eye?  
Instead of looking at your brother's fault, look at his need.

4 How can you say to your brother, ‘Let me take the speck out of your eye,’ when all the time there is a plank in your own eye?  
If you don't see your brother's need you cannot meet your brother's need.

5 You hypocrite, first take the plank out of your own eye, and then you will see clearly to remove the speck from your brother’s eye.  
Forgive your brother his fault, assess the need and address the need.

6 “Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and then turn and tear you to pieces.
Unbelievers will reject God's wisdom (and you) until they are ready to receive it.

(Jesus words from Matthew 5:1-6, NIV84)
(My imperfect understanding of the passage.)