Let us consider first how a father loves his son. Parents love their children even before they are born. At first, their love is a powerful instinct. But instinct is appropriated and surpassed as they give of themselves continuously for the growth and formation of their children. Parents teach their children what they know to be good and evil, and thus form their children to be like themselves.

Furthermore, parents raise their children not only to know and to love what is good but to do so freely, independently of the guidance of the parents. The result is a unique and twofold relationship. First, parents see in their children their own effort to serve their children’s health and knowledge and virtue while the children were dependent upon them. And second, parents see in their children, in their independence, the free and mature decision to love what is good and to enjoy the friendship of their parents. For parents, this is the special, double joy of their vocation.

This special relationship and joy are even clearer between mothers and daughters and between fathers and sons, since mothers are models especially for their daughters, and fathers especially for their sons. And in the latter case it is perhaps clearer still because fathers have less help from instinct and sons more opportunity to stray. To understand the words of St. John, then, we must attend to this supreme joy – the delight of a father in his son.