Theology is not merely about living: it is about living for God, through Christ. Its chief end is God’s glory, and the great means it seeks to that end is our union and communion with God (103), which comes only through the Mediator, Jesus Christ (102).

Previously I discussed how Petrus van Mastricht, in the recently translated prolegomena of his Theoretical-Practical Theology, taught me to submit to the Word of God (part 1), and how he gave me a biblical and balanced view of the use of reason in theology (part 2). In this third and final part I discuss what was the most life-changing for me, and I trust for many who will read it: Mastricht’s definition of theology itself as “the doctrine of living for God through Christ” (98).

Theology is for living.

 In defining theology Mastricht takes his start from Paul’s words in 1 Timothy 6:3, that doctrine is “according to godliness” (63, 98), and from there builds his definition, arguing that everything in Scripture points to the end of living for God (Rom. 6:11; 2 Cor. 5:15; Rom. 14:7-8; Col. 3:3-4; Phil. 1:20-21; p. 98), and moreover, as faith without works is dead (James 2:17), and knowledge without love (1 Cor. 8:1; 13:1-2), so is doctrine without practice. Theology is not, therefore, merely theoretical. Nor is it mixed, partly theoretical and partly practical, as if some doctrines should be practically applied and others not. Indeed, though Mastricht’s title, Theoretical-Practical Theology, describes his method–every chapter treats theory (exegesis, dogmatics, and elenctics), then practice–it does not describe theology itself, which he insists is entirely and preeminently practical (106-107).

Mastricht is sure that no Christian will differ from his definition of theology, if not in words, at least in substance (104). Such a definition is manifestly biblical, and such a theology as it defines meets the manifest need of our world, and of our churches: not talk, but power (1 Cor. 4:20), not a dead faith (James 2:17), but a faith working through love (Gal. 5:6).

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