Admonition XI: Let no one be corrupted by the evil of another
When speaking of envy in Admonition VIII, Francis warned us against envy by    pointing out that the good done by people is done in them by the action of grace    and of the Holy Spirit. So to envy others is to presume that God is not as active    in our lives. But the only action that is not a product of grace is sin. Sin    should displease us but the important thing to know is how and why it should    displease us. Francis says quite clearly that we are not to be disturbed and    angry at sin in other people. We are to be disturbed and angry not because of    the sin but because of our love for others. To be angry over sins in other people    is to store up guilt for ourselves. Behind these words, that are at first difficult,    there is the reality that we are not to judge others because we cannot see into    the conscience of another person. We can see a sinful action but we cannot read    a human heart and know whether or not a person has sinned in his or her heart.    But we do know what is in our own conscience and when we act against conscience.    We are fully aware of our own sins. These must disturb and make us angry because    they offend God. In this context Francis quotes Matthew's Gospel: Return to    Caesar what is Caesar's and to God what is God's [22:31]. As Francis uses this    text, Caesar applies to other people to whom we must extend love not anger while    we must show to God obedience, for we must obey God and not sin.