James Four Eleven-Seventeen
Do not speak evil of one another, brethren. He who speaks evil of a brother and judges his brother, speaks evil of the law and judges the law. But if you judge the law, you are not a doer of the law but a judge. There is one Lawgiver, who is able to save and to destroy. Who are you to judge another? Come now , you who say, “Today or tomorrow we will go to such and such a city, spend a year there, buy and sell, and make a profit”; whereas you do not know what will happen tomorrow. For what is your life ? It is even a vapor that appears for a little time and then vanishes away. Instead you ought to say, “If the Lord wills, we shall live and do this or that.” But now you boast in your arrogance. All such boasting is evil. Therefore, to him who knows to do good and does not do it, to him it is sin.

Every wicked act dulls the sense of our thoughts and gives birth to arrogance. For although it is necessary for each one to examine himself and behave according to God’s will, many people do not do this but prefer to mind the business of others. If they happen to see others suffering, it seems that they forget their own weaknesses and set about criticizing them and slandering them. They condemn them, not knowing that they suffer from the same things as the people they have criticized, and in so doing they condemn themselves. The wise Paul writes exactly the same thing: “If you judge another in something, you condemn yourself, for the one who judges does the same things.

St Cyril of Alexandria