In 1967 Karl Rahner famously wrote: ""The economic Trinity is the immanent Trinity, and vice versa."" From that time onwards, Rahner's Rule has become the norm for conceiving the relationship between the Trinity in the economy of salvation and God's eternal inner life. Evangelical theologians currently employ Rahner's Rule in a variety of ways. One of the most popular is the ""Strict Realist Reading"" whereby trinitarian relationships in salvation history are taken to mirror eternal relationships within God. This book brings this norm into conversation with the witness of Scripture in order to assess its viability. In doing so, it highlights troubling issues that arise from the application of the Strict Realist Reading of Rahner's Rule to the narrative of Luke-Acts. This book suggests that the Strict Realist Reading can be shown to be a questionable basis for our doctrine of God's inner life.