If a brother's fault can be public and obvious, you should justify it with love and brotherhood, and say that God allowed that brother to fall into this fault because other virtues are hidden in him to protect them, or if he has had that defect for a short period of time, it is to keep him more humble in his own eyes and even with the contempt of others to bear some fruit of humility and to please God more, and thus his gain will be greater than his loss. If, again, someone's sin is not only obvious but also great and comes from a stubborn heart, do not judge him but run with your mind to the fearful judgments of God and you will see there other people who, while previously in great transgression, have reached great measures of holiness through repentance, and others, again, who while previously in the highest degree of perfection, have fallen into a most wretched abyss.
Therefore, always stand with fear and trembling, more for yourself than for anyone else. And be sure that all those good words you will say about your neighbor and the joy you will feel for him are the fruit and result of the Holy Spirit. Conversely, every contempt and arrogant judgment and slander of your neighbor comes from our wickedness and from diabolical incitement.