D.A. Carson writes:
This present volume is the joint product of a Neutestamentler and a systematic theologian. In their colaboration they have simultaneously attemped a detailed exegetical and theological understanding of what the Fourth Gospel says about God, using the categories of that Gospel itself, and mature understanding of the links between that text and the systematic formulations of what came to be called the doctrine of the Trinity. In what sense is it proper to think of the doctrine of God in John's Gospel as trinitarian? Some are so suspicious of links between biblical exegesis and systematic theology that they will deplay any ostensible connections between the two, afraid that the latter will domesticate the former and stain it with anachronism, or that the former will dilute the latter and render it insipid. Drs Kostenberger and Swain, thankfully, are not numbered among them. For those who want to know what they ought to believe--surely one of the functions (though not the only one) of constructive systematic theology--out of God's self-disclosure in Scripture, this book will be a stimulating delight. In addition to its contribution to Christian understanding of God (can there be any higher subject?) it stimulates serious thought about how we move from careful study of biblical text to theological formulation. Nothing would please us more than if this book were to become a model for a lot more theological work of the same order.