Olivier-Maurice Clément (1921 – 2009) – was an Orthodox Christian theologian, who taught at St. Sergius Orthodox Theological Institute in Paris, France. There he became one of the most highly regarded witnesses to early Christianity, as well as one of the most prolific.
“We are made in the image of God. From all eternity there is present in God a unique mode of existence, which is at the same time Unity and the Person in communion; and we are all called to realize this unity in Christ, when we meet him, under the divided flames of the Spirit. Therefore we express the metaphysics of the person in the language of Trinitarian theology. What could be called the ‘Trinitarian person’ is not the isolated individual of Western society (whose implicit philosophy regards human beings as ‘similar’ but not ‘consubstantial’). Nor is it the absorbed and amalgamated human being of totalitarian society, or the systematized oriental mysticism, or of the sects. It is, and must be, a person in a relationship, in communion. The transition from divine communion to human communion is accomplished in Christ who is consubstantial with the Father and the Spirit in his divinity and consubstantial with us in his humanity. […]
In their expositions of the Trinity, St. Basil and St. Maximus the Confessor emphasize that the Three is not a number (St. Basil spoke in this respect of ‘meta-mathematics’). The divine Persons are not added to one another, they exist in one another: the Father is in the Son and the Son is in the Father, the Spirit is united to the Father together with the Son and ‘completes the blessed Trinity’ as if he were ensuring the circulation of love within it. This circulation of love was called by the Fathers perichoresis, another key word of their spirituality, along with the word we have already met, kenosis. Perichoresis, the exchange of being by which each Person exists only in virtue of his relationship with the others, might be defined as a ‘joyful kenosis‘. The kenosis of the Son in history is the extension of the kenosis of the Trinity and allows us to share in it.” From: The Roots of Christian Mysticism, Texts from the Patristic Era with Commentary, pp. 65-67.