Systematic Theology

Robert Letham

• Publisher: Crossway
• Year: 2019
• ISBN:
  9781433541339
• Topic: Theology & Religion
• Subtopic: Christian Theology

This comprehensive systematic theology by respected theologian Robert Letham covers the whole field of Reformed Christian doctrine from biblical, historical, and theological angles.

Letham begins with God's ultimate selfrevelation as the Father, the Son, and the Holy Spirit in indivisible union, continuing on with the works of God in creation, providence, and grace. He draws deeply from Scripture and important voices from the church to provide a clear and concise articulation of the Reformed faith. He also addresses current issues such as feminism, charismatic gifts, sexual ethics, environmentalism, other religions, the nature of truth, and civil liberties. Each chapter is followed by discussion questions, with a glossary of terms included at the end.

This work grounds theological understanding and practice in the life and ministry of the church, accessible to pastors, students, scholars, and anyone who desires to understand, believe, and live scriptural doctrine more fully.

Part 1

The Triune God

Almighty and everlasting God, who has given to us your servants grace by the confession of a true faith to acknowledge the glory of the eternal Trinity, and in the power of the divine Majesty to worship the Unity; we beseech you, that you would keep us stedfast in this faith, and evermore defend us from all adversities, who lives and reigns, one God, world without end. Amen.

Collect for Trinity Sunday, Book of Common Prayer (1662)

1

The Revelation of God

The Bible never attempts to prove that God is. Attempts to do so by logic fall short of establishing the God and Father of our Lord Jesus Christ. God exists necessarily—there is no possibility that he cannot exist. The existence of God is not rationally attained, though it can be rationally explained and defended. Rather, God reveals himself in the world around us and has implanted a knowledge of his existence in all people, evidenced in the almost universal recognition of the need to worship a higher being. This implanted revelation is clear and fulfills the purpose God has for it, but it does not disclose the gospel and so cannot lead us to salvation. Nevertheless, it is essential as a basis for knowing God.

A few years ago, a group of atheists, which included the British Humanist Association, paid for a poster on the sides of London double-decker buses. The poster said: “There’s Probably No God. Now Relax and Enjoy Your Life.”1 Along similar lines, the geneticist Richard Dawkins has argued that the claim that there is a god has a very low probability, though Dawkins stopped short of zero. “I think God is very improbable and I live my life on the assumption that he is not there,” he acknowledged.2 Again, “I am agnostic only to the extent that I am agnostic about fairies at the bottom of the garden.”3

I couldn’t agree more. If anything, the advertisers didn’t go far enough. The god who is a product of the constructions of human thought and the predication of whose existence depends on human reasoning does not and cannot exist, since in any argument the premises have a higher degree of certainty than the conclusion to which the argument leads. Such argumentation could never establish that the God and Father of our Lord Jesus Christ is.

The Bible nowhere attempts to argue for the existence of God. It assumes that God is and that he has revealed himself; God is the necessary presupposition for human life, so much so that it is the fool who has said in his heart that there is no God (Ps. 14:1). Centuries ago the then archbishop of Canterbury, Anselm (1033–1109), wrote that God is that than which none greater can be thought. Necessary existence is entailed in that. If one were to conceive of a being that might not exist, one would not have conceived of One who is the greatest that can be thought, since it would be possible to conceive of a greater, about whom nonexistence is not predicable.

R. C. Sproul has gone a stage further, arguing strongly and correctly that, in an important sense, God does not exist.4 From a different angle, if one has a hankering for etymological fallacies5—one does from time to time, doesn’t one?—we can see how this works out. Our verb “to exist” is ultimately derived from the Latin verb exsistere, meaning, among other things, to come into view, to come forward, to come into being.6 This entails being out of or from another entity. All things created are what they are in this way, derived from something else. We exist from our parents, our children exist from us, my desk comes from a tree, which in turn is derived from an acorn, which fell from another tree, and so on. The building in which I work was produced from a range of materials. The air we breathe, our planet, and its galaxy are all brought about by other entities. All such entities are in a constant process of change, growth, retraction, and flux. All things in the universe exist contingently. Once they did not exist; their present existence depends on God, while the possibility of their ceasing to be is ever present. This is not the case with Yahweh, the God of Israel, the God and Father of our Lord Jesus Christ. He is. He is life itself. Created entities exist; but God is. As Aquinas wrote, God is his own existence—he is above existence and exceeds every kind of knowledge.7 He subsists, for “those things subsist which exist in themselves, and not in another.”8

With these important provisos, we will accommodate ourselves to popular usage. There are a range of arguments devised to prove or to explain that God is.

1.1 Arguments for the Existence of God

One class of arguments for the existence of God might be intended to persuade an unbeliever. Not only does the Bible not follow...