This must also lead then to reconceiving our understanding of salvation, they argue. Salvation is to be understood as being welcomed into the trinitarian perichoresis, the “divine embrace of love.” Let's unfold this statement.
[Part 13 in a series on New Wine and systematic theology, drawn from my research master thesis Life to the Full. From Creation to Re-Creation, VU University 2014]
Both with Moltmann and Pannenberg, then, their reconceiving of the Trinity leads to a reconceiving of the relationship between God and the world, and to new perspectives on salvation. Through his salvation, God communicates himself. Salvation is to be understood as being welcomed into the trinitarian perichoresis, the “divine embrace of love.” But what does this mean? How are human beings supposed to “participate” in the divine perichoresis? What is the substance of salvation?
In traditional theology, Moltmann asserts, the doctrine of the opera trinitatis ad extra expressed what God means to the world. But this doctrine was incapable of expressing what the world means for God. The concept of the divine perichoresis is capable of doing that. It sheds light on how the essence of the triune God is all about loving relations, about self-giving love, in a deeply reciprocal way. As much as this is true for the opera trinitatis ad intra (God’s inward actions), it is for the opera trinitatis ad extra (God’s outward actions), Moltmann asserts, because God’s character and identity are expressed in his outward actions.
God’s relation with the world, then, reflects God’s inner being. It truly is a living, two-way relationship, Moltmann argues. It must have a reciprocal character - after all, a purely one-sided relation would not be a living relation at all.  Moreover, as it reflects the intratrinitarian perichoresis, it must be aimed at mutually self-giving love, rejoicing in one another, glorifying one another, permeating one another.
Love finds fulfilment and bliss when it is returned. Likewise, the love of God for his creation and the love of creation for its Creator, finds fulfilment and bliss when they are reciprocal. God not merely wants to communicate himself to himself (in the eternal divine life), he wants to communicate himself to his creation as well. God desires to dwell in his creation and to fill the whole earth with his glory.
When God created man “in the image of God” (Genesis 1:2f; Psalm 8), this meant both a destiny and a promise. Man was meant to abide in God, rejoice in him and glorify him, as God desired to dwell in man, rejoice in him, and glorify him. But creation had to await the appearance of this “true man” that truly corresponds to God, in him this destiny would come true. The intimacy between Jesus and the Father, their reciprocal, self-giving and glorifying love, is the divine embrace of love that people are invited into.
Moltmann thus sees a tight connection between God’s perichoretic being and the salvific work of the Son.
“If the Son becomes ‘man’ that is to say, the image of God - then he communicates his responsive love to those who are destined for manhood and womanhood - destined, that is, to be the image of God; he gathers them into his relationship of sonship to the Father and communicates to them his own liberty, which is above the world. In this way the incarnate Son glorifies the Father in his world and perfects humanity’s creation, which destines men and women to be the image of God.”
Salvation, then, principally means to be taken up in Christ’s relation of sonship to the Father and to be transformed into his image, to become human as God intended human beings to be. This is dependent on the work of the Spirit, by whom human beings are to be “resurrected into a new life” with Christ.
This “eschatological work of the Spirit” can’t be interpreted merely spiritually in some Neo-Platonic or gnostic way, Moltmann argues, but it comprises the bodily, earthly, material reality. The experience of the Spirit is quite distinct from “human forms of spiritualization and sublimation”, Moltmann asserts (without further explanation), and it is “always a physical experience.” It is “physical resurrection, physical transfiguration, and transformation of the physical form of existence.” It is a resurrection into the freedom of God, incomplete as it will remain in the present age.
With the resurrection, transfiguration, transformation and glorification of Jesus, the general outpouring of the Spirit “on all flesh” begins.
“In the Spirit people already experience now what is still to come. In the Spirit is anticipated what will be in the future. With the Spirit the End-time begins. The messianic era commences where the forces and energies of the divine Spirit descend on all flesh, making it alive for evermore. In the activity of the Spirit, consequently, the renewal of life, the new obedience and the new fellowship of men and women is experienced.”
It is through the indwelling of the Spirit, that “the completion and perfecting of creation of human being and all things” begins, “which makes them the home of the triune God.” Through the indwelling of the Spirit that God as a matter of speaking “comes to be at home in his own world.”  It is through the indwelling of the Spirit, then, that salvation is brought about - salvation that means to be welcomed into the divine perichoretic life, bringing fulfilment of being. This remains incomplete until the end of times. But when the Kingdom of God is consummated and fully will be the “Kingdom of Glory”, human beings will experience “the unhindered participation in the eternal life of the triune God himself, and in his inexhaustible fullness and glory.”
Again, Moltmann’s presentation is problematic for several reasons. He does not explain how the Son “communicates his responsive love” to men and women, or how he “gathers them into his relationship of sonship to the Father.” Instead of the traditional notions of Christ’s atoning work that is to be appropriated by faith and conversion, Moltmann rather suggests a universal completion of creation - in Christ, and through a universal outpouring of the Spirit “on all flesh” (suggesting “all mankind”). Clearly, Moltmann does not want to restrict the scope of salvation to those who profess Jesus Christ as Lord and Saviour, but propagates a universal salvation that flows from the basic structure of his theology.
Furthermore, his account of “the completion and perfecting of creation of human being and all things”, making them “the home of the triune God” can be read from a Reformed or Evangelical perspective, but his language and imagery is too reminiscent of Bloch’s philosophy to ignore.
Likewise, the unreserved way in which Moltmann speaks of “the unhindered participation in the eternal life of the triune God himself” - suggesting a deification in which the finite becomes infinite (or perhaps rather entailing the becoming immanent of the divine) - must be understood rather from Moltmann’s philosophical frame of reference than from Biblical theology.
We already saw how Pannenberg - in his argument on the unity of God - affirmed that the historical relations of God to the world cannot be external to the interior life of God. God is fulfilled through his relationship to the world, as the world freely submits to him and acknowledges his reign, responding to his love in the pattern of the Son, in the Spirit. In contrast to Moltmann, however, Pannenberg maintains the sovereignty of God, as this fulfilment depends on the triune God himself, on his faithfulness to his creation.  Likewise, human beings – created in the trinitarian image of God - can only find fulfilment through their perichoretic relationship with God.
Like Moltmann, Pannenberg argues that this occurs through the indwelling of the Spirit (thus understanding salvation in pneumatological terms). Pannenberg comes very close to Moltmann, but in contrast to Moltmann he emphasizes that this Spirit of sonship is given only to “Christians”, to those who are “obedient to Christ”, and participation in Christ is mediated by the Spirit to “believers.”
According to Pannenberg, then, salvation flows from the inner being of God and must be understood as being welcomed into the divine trinitarian life, through the indwelling of the Spirit. It is bound up with the Kingdom of God, as salvation means to enter into the Kingdom and to participate in the rule of God in the world. The new life of believers is the “life in the Spirit.”
As we have seen, Pannenberg agrees with Moltmann that the Bible does not allow a merely spiritualized interpretation of what this “participation in the Kingdom of God” means. Messianic salvation is about wholeness of life, addressing issues of social injustice, violence, oppression, alienation, bondage, sickness and death. Through the indwelling of the Spirit, creaturely life will be made whole as it participates in the divine trinitarian life and the Kingdom of God. This wholeness of life “cannot be achieved, however, in the process of time”, Pannenberg asserts, more carefully than Moltmann (and his utopian, revolutionary inspiration) - it “depends on the future”.
“The focusing of salvation on the eschatological future of God stands in critical opposition to all achievement of human life in this world alone, for in striving for self-fulfilment in this world, we close ourselves off to God and his future.”
Part 12: Salvation & the Trinity (1): The Divine Dance of Love - Reconceiving the Trinity
 Moltmann, The Trinity and the Kingdom, 98-99.
 Moltmann, The Trinity and the Kingdom, 98.
 Moltmann, The Trinity and the Kingdom, 108, 117.
 Moltmann, The Trinity and the Kingdom, 118.
 Moltmann, The Trinity and the Kingdom, 123-124.
 Moltmann, The Trinity and the Kingdom, 124.
 Moltmann, The Trinity and the Kingdom, 125.
 Moltmann, The Trinity and the Kingdom, 222.
 Pannenberg, ST I, 438.
 For instance Pannenberg, ST I, 266; ST II, 397-403. Also explicitly so, ST III, 604, “The inbreaking of the present of the coming kingdom is granted to others also insofar as they accept the message of Jesus and open themselves to his work.”
 The final chapter of his Systematic Theology, on the consummation of creation in the Kingdom of God, Pannenberg puts it as strongly as this, “God and his lordship form the central content of eschatological salvation”(ST III, 531).
 Pannenberg, ST II, 399. At the same time – upholding the tension between the “already” and “not yet” of the Kingdom of God - Pannenberg asserts that the apostle Paul is clear that “in and by Jesus future salvation is opened up for believes and can be attained now” (ST II, 400). “Hence the presence of the Spirit also means already the overcoming of sin and death. If sin and death are to be finally overcome only in the eschatological consummation, victory over them is already in process in the present work of the Spirit, and above all in his presence as a gift in believers” (ST III, 553).