The fundamental fact of reality is God as Father, Son, and Holy Spirit. God could have decided not to make the world. He could have chosen to simply remain “alone.” But there is no possible world in which God does not exist as Father, Son, and Holy Spirit. They are a community of love. They are always such a community. They always will be.

So, even though they could have created the world in many different ways, they would never consider creating a world that didn’t reflect that fundamental reality—their social nature as Father, Son, and Holy Spirit. When the human race is created in God’s image, the Bible makes it clear that the Divine image is related not only to each individual man or woman, but also to a human family or community:

So God created man in his own image,
in the image of God he created him;
male and female he created them.

This would lead us to expect that Trinitarian relationships are the model for social relationships. We can hardly avoid this conclusion for parents and children when we worship and read about Father and Son. But also we find it for wives and husbands: “But I want you to understand that the head of every man is Christ, the head of a wife is her husband, and the head of Christ is God” (First Corinthians 11.3).

One way the Apostle Paul exhorts Christians in marriage is to recognize a mutual dependence or interdependence. He tells the husband, “In the same way husbands should love their wives as their own bodies. He who loves his wife loves himself. For no one ever hated his own flesh, but nourishes and cherishes it, just as Christ does the church…” (Ephesians 5.28, 29). That “body” solidarity is also invoked by Paul to describe relationships in the Church (First Corinthians 12).   The church is one body so that all the members of the Church, like the organs or parts of a living body, all contribute to the good of the rest.

For the body does not consist of one member but of many. If the foot should say, “Because I am not a hand, I do not belong to the body,” that would not make it any less a part of the body. And if the ear should say, “Because I am not an eye, I do not belong to the body,” that would not make it any less a part of the body. If the whole body were an eye, where would be the sense of hearing? If the whole body were an ear, where would be the sense of smell? But as it is, God arranged the members in the body, each one of them, as he chose. If all were a single member, where would the body be? As it is, there are many parts, yet one body.

The eye cannot say to the hand, “I have no need of you,” nor again the head to the feet, “I have no need of you.” On the contrary, the parts of the body that seem to be weaker are indispensable, and on those parts of the body that we think less honorable we bestow the greater honor, and our unpresentable parts are treated with greater modesty, which our more presentable parts do not require. But God has so composed the body, giving greater honor to the part that lacked it, that there may be no division in the body, but that the members may have the same care for one another. If one member suffers, all suffer together; if one member is honored, all rejoice together (First Corinthians 12.14-26).

But what about relationships that are less intimate? What about the insurance salesman or the cashier at your local grocery store? How do those relationships model on the Trinity? Even though the word “relationship” can seemed stretched by applying it to strangers whom you only know through transactions, there still seems a way in which the word applies and the Trinity applies as a model. Jesus pointed to a fundamental way in which the persons of the Trinity relate to one another: “Father, the hour has come; glorify your Son that the Son may glorify you” (John 17.1). This passage appears related to many others about mutual glorification that takes place in the Trinity The Father, Son, and Holy Spirit exist in a mutual interchange. It seems to work very much in the same way the Church functions as a body with diverse members according to First Corinthians 12.14-26). Indeed, Augustine of Hippos saw this in the Holy Spirit, of which he wrote:

But the relation is not itself apparent in that name, but it is apparent when He is called the gift of God; for He is the gift of the Father and of the Son, because “He proceeds from the Father,” as the Lord says; and because that which the apostle says, “Now, if any man have not the Spirit of Christ, he is none of His,” he says certainly of the Holy Spirit Himself. When we say, therefore, the gift of the giver, and the giver of the gift, we speak in both cases relatively in reciprocal reference. Therefore the Holy Spirit is a certain unutterable communion of the Father and the Son; and on that account, perhaps, He is so called, because the same name is suitable to both the Father and the Son. For He Himself is called specially that which they are called in common; because both the Father is a spirit and the Son a spirit, both the Father is holy and the Son holy. In order, therefore, that the communion of both may be signified from a name which is suitable to both, the Holy Spirit is called the gift of both (The Trinity, Book 5, Chapter 11).

Augustine correctly sees that the “gift of the Spirit” given from God to the Church is a reflection of the eternal reality that the Spirit is given by the Son to the Father and vice versa. They are in an eternal interchange of love. Humanity, made in God’s image, is created and then redeemed to reflect this in human relationships.

What is an intimate and relatively unquantifiable interchange in intimate human relationships (husband and wife) translates to exchange among those relationships that are not so intimate. None of us are independent. We need one another and we help sustain each other through mutual cooperation in trading or exchanging goods. God made us to be this way.