"Judge not, that you be not judged. For with what judgment you judge, you will be judged; and with the measure you use, it will be measured back to you. And why do you look at the speck in your brother's eye, but do not consider the plank in your own eye? Or how can you say to your brother, 'Let me remove the speck from your eye'; and look, a plank is in your own eye? Hypocrite! First remove the plank from your own eye, and then you will see clearly to remove the speck from your brother's eye." (Matthew 7:1-5)
Commentary: "We must judge ourselves, and judge of our own acts, but not make our word a law to everybody. We must not judge rashly, nor pass judgment upon our brother without any ground. We must not make the worst of people. Here is a just reproof to those who quarrel with their brethren for small faults, while they allow themselves in greater ones. Some sins are as motes, while others are as beams; some as a gnat, others as a camel. Not that there is any sin little; if it be a mote, or splinter, it is in the eye; if a gnat, it is in the throat; both are painful and dangerous, and we cannot be easy or well till they are got out. That which charity teaches us to call but a splinter in our brother's eye, true repentance and godly sorrow will teach us to call a beam in our own. It is as strange that a man can be in a sinful, miserable condition, and not be aware of it, as that a man should have a beam in his eye, and not consider it; but the god of this world blinds their minds. Here is a good rule for reprovers; first reform thyself." - Matthew Henry
"These verses are one of those passages of Scripture, which we must be careful not to strain beyond its proper meaning. It is frequently abused and misapplied, by the enemies of true religion. It is possible to press the words of the Bible so far that they yield not medicine, but poison.
Our Lord does not mean that it is wrong, under any circumstances, to pass an unfavorable judgment on the conduct and opinions of others. We ought to have decided opinions. We are to "prove all things." We are to "try the spirits." Nor yet does He mean that it is wrong to reprove the sins and faults of others, until we are perfect and faultless ourselves. Such an interpretation would contradict other parts of Scripture. It would make it impossible to condemn error and false doctrine. It would debar any one from attempting the office of a minister or a judge. The earth would be "given into the hands of the wicked." (Job 9:24.) Heresy would flourish. Wrong-doing would abound.
What our Lord means to condemn is a censorious and fault-finding spirit. A readiness to blame others for trifling offences, or matters of indifference--a habit of passing rash and hasty judgments--a disposition to magnify the errors and infirmities of our neighbors, and make the worst of them--this is what our Lord forbids. It was common among the Pharisees. It has always been common from their day down to the present time. We must all watch against it. We should "believe all things," and "hope all things "about others, and be very slow to find fault. This is Christian charity. (1 Cor. 13:7.)" - JC Ryle