The moral law requires more of us than that we not treat others as means; in addition, the personality of the other must be treated as an end. So beyond the negative duties of justice, there are the positive duties of charity. We can't remain content simply to avoid undermining the other's personality but should do everything possible to help him realize and develop it. To the formula of the moral law that sums up justice in the phrase “Don't do to others what you wouldn't want done to you” must be added the formula of charity: “Do unto others as you would have done to you.” In other words, don't rest content with seeing to it that your own personality remains intact. Seek to enlarge your personality, and help others to do the same.

Like the duties of justice, those of charity can be deduced from the moral law. Because the person of the other consists of a body and a soul, we must work not just to avoid injuring both but to support them and, if the need arises, to care for them. The duty of charity toward the body of another requires that we look after his health.

As for the soul, we must again distinguish between three faculties: sensibility, intelligence, and activity. For sensibility, the courtesy demanded by justice becomes, in the context of the duties of charity, benevolence.