Who is God in the Old Testament? Retrieving Aquinas after Rahner's Answer

Karl Rahner adamantly argued that the God of the Old Testament is the unoriginate Person of the Father. This forms the bedrock of his trinitarian theology, often credited as renewing Christian appreciation for the Trinity. However, his position that the Old Testament God must be identified as the Father contradicts much of the Christian tradition, including strands of Greek theology whose emphasis on the Father he claimed to restore to the West. This article retrieves the theology of Thomas Aquinas after Rahner in order to correct the imbalance of Rahner's position with greater nuance in appreciating the mystery of God in the Old Testament.