What do human beings like best? That is the most important question in human history. People on the whole most likely want something related to themselves to be the best. They want their family, nation and world to be the best one. Then, what is the most proper way of thinking? It is the way to think in the other's shoes. One can't escape from the relative relationship.

From this point of view, what is the best in a family? It is not money, knowledge or power, but parents. What is next? It is the lovely spouse, and finally the children. Then, why do you think parents, husband and wife, children are good? It is because love is involved in each part. In other words, there are parental love, which is essential to the children, conjugal love, which is essential to the husband and wife, brotherly love and children's filial heart toward the parents. (112-290)

Just as a type of iron which has more magnetic elements is stronger in a magnetic force, so you feel a different extent of feeling according to the depth of relationship. So it is natural that siblings are inclined to feel more intimate and love. It is because of the historically close relationship by which they are bound together. Why do mothers and fathers love their children? It is because the children originate from their parents. Therefore, if the parents' natures were taken out of their children, there would be no nature left. Whether it is a son or daughter, the child stems from the parents. One is born taking after the natures of one's parents. Without his or her parents' natures, a child will become a being who has neither nature nor relationships. (50-264)