“But from the beginning of creation, God made them male and female. 

For this reason a man shall leave his father and mother

and be joined to his wife,

and the two shall become one flesh.

So they are no longer two but one flesh. 

Therefore what God has joined together,

no human being must separate.”

God is love. The revelation of the Trinity, both in itself and as the Father, Son, and Holy Spirit act in the history of salvation, provides profound depth to our understanding of love. Distinct in persons, but one in being, God is not an abstract idea of love, but actual relations between divine persons. One in substance, the Father eternally begets, the Son is eternally begotten, and the Holy Spirit eternally proceeds from the Father and the Son. The three coequal and coeternal divine persons are one in nature, essence, will, power, and action. The communion of the three persons is sometimes described as interpenetration. It is an intimate relationship of mutual envelopment, or perichoresis, which goes beyond a more modern appropriation of the Greek term that signifies dancing together, to a sense of mutual indwelling. Although it can provide some insight, the Father, Son, and Holy Spirit aren’t just performing a coordinated and intricate dance. Each divine person is a home for the others and is, likewise, at home in the others. Beginning with our creation in the image of God, St. Augustine wrote that love, itself, is Trinitarian, consisting of the lover, the beloved, and the love between them, like the Father, the Son, and the Holy Spirit. Love is not abstract, it is found in the relationship between persons. 

In the history of salvation, the pinnacle of the mutual indwelling of love is between Jesus and the Church. With a fully divine and fully human nature, the person of the Son, of Jesus the Christ, of the Word Incarnate, of Emmanuel, makes real God with us. He dwells within his people, the Church. He is the head of his body, the Church. Perichoresis is used, as well, to describe the mutual envelopment of the divine and human natures in the second person of the Trinity. In a sense, this is therefore true of the Church: it is a complex reality with both human and divine elements. In the Old Testament, God repeatedly formed covenants with his people, Israel. A covenant is different than a contract. In a contract, the parties have responsibilities and rights which are governed by the terms of the contract. In a covenant, a new entity or relationship is formed with a communion of the parties. Both parties give 100% to the other and create a new reality. (I will be their God and they will be my people). It’s not 50/50 or 40/60 or 25/75. It is more like a merger than an agreement. In the new and eternal covenant, Jesus gave himself completely, his life upon the cross as a covenantal sign, renewed in each Eucharist, to create a new entity, the Church. That the two, Jesus Christ and the Church, should become one, St. Paul calls a great mystery, a sacrament. 

In the created realm, the pinnacle of the mutual indwelling of love is between a husband and a wife. It was so from the beginning. Marriage is a covenant, not a contract. The wife and the husband give themselves completely to the other and a new entity is created. The two become one flesh. In the ideal, they become home for each other, a mutual indwelling of persons. In the secular world, there is an argument that religions create God in their own image. Whether God created us in his image or vice versa, God is love, not abstractly lovely. God is the real relationship between lover, beloved, and the love that is shared. It is what is best about God, and best about us