Well now from Pannenberg’s understanding of revelation to the Trinity. I think it will take three parts too, but all of Pannenberg’s Systematic Theology is an exposition of the Trinity.
If Jesus is to be the Word of God, he is properly understood as the eternal Son and, therefore, the immanent Trinity receives priority over all other parts of the doctrine of God. This is one of Pannenberg’s more unique developments. He comes to this conclusion by an examination of the teaching and ministry of Jesus in which the divine reign of the Father that was present in his life brought a significant relationship. For Pannenberg “the fellowship of Jesus the Son with God as Father can obviously be stated only if there is reference to a third as well, the Holy Spirit” (I, 267). The presence of the Spirit in the work of Jesus and in the fellowship of the Son with the Father is the ultimate basis that the Christian doctrine of God is found definitively in Trinitarian form. The Trinity is proper explication of the self-revelation of God. The Trinity is then the primary category for developing a doctrine of God and not, as in the past, added to God following the development of God’s essence and attributes. His primary concern is the demonstration that the immanent Trinity is the eternal God revealed in Jesus. Therefore, “God in eternity is Father only in relation to him,” the eternal Son (I, 310). The self-differentiation of the Son from the Father became the key for making Trinitarian distinctions. For Pannenberg, the Trinity all participates in the monarchy of the Father and this occurs without subordination because only by the work of the Son is the kingdom established in creation and only by the work of the Spirit is creation consummated so that the three persons are consubstantiated in each other (I, 324-325). It is then not the common work that brings unity to the three persons, but their relational conditioning. The conclusion is that the God being revealed or self-actualized in history is the eternal God, the immanent Trinity. The coming eschatological consummation is only the locus of the assessment that the Trinitarian God is always the true God from eternity to eternity. The dependence of his existence on the eschatological consummation is simply necessary to take into account the “constitutive significance of this consummation for the eternity of God” and therefore the Kingdom of God plays an important role in the demonstration of the Trinity, namely that in its coming it gives retrospective confirmation to the Triune identity of God (I, 331). For Pannenberg, the unity of God within the movement from creation to consummation must be in the Trinity of persons and so their relationships prove to be the basis of distinction and unity in both the immanent and economic Trinity.