The theological method of Martin Luther is aptly summed up in the Reformation cry of “sola scriptura” (scripture alone). He did not consider church tradition to be on par with scripture, and his guiding principle of reading scripture was “was Christum treibet” (what drives Christ). This is to say, all scripture is about Christ.

The crux of Luther’s theology is the theology of the cross. This works itself out in the following three ways:

• Hermeneutically as “law and gospel”.
• Politically as his doctrine of the “two kingdoms”.
• Existentially as “simil iustus et peccator” (righteous and sinner at same time). This is where for Luther the law and gospel encounter each individual simultaneously.

The scripture that encapsulates Luther is Romans 7.15: “I do not do what I want, but I do the very thing I hate.” Luther interpreted the plight of the man in Romans 7.14-25 as something that all Christians go through; it is the war waging in us between the law and the gospel.

Jürgen Moltmann’s theological method is best described as ad-hoc and eclectic. He employs scripture to support his theology, but he is not driven by the need to derive his theology from scripture. He somewhat respects church tradition and the church fathers, but he is in no way beholden to them. In fact, he has no qualms at bringing in other resources use in his theological dialogue (e.g. Kabbalah, mysticism, science, psychology). He uses this method to prevent the petrification of theology and to bring about change to the church’s way of thinking.

While Moltmann does not exactly see eye to eye with Luther when it comes to theology, he was nevertheless influenced by Luther (through other theologians e.g. Barth, Iwand), which comes across quite obviously in their respective theologia crucis.  Moltmann also does not view scripture through the “law and gospel” dichotomy, and neither does he accept Luther’s two kingdoms theory. One criticism he has against it is that Germany showed that the two kingdoms viewpoint did not provide a basis for resisting the Nationalist Socialist party. Moltmann’s own political theology derives from the Barthian concept of an all-encompassing lordship of Christ. Moltmann thinks that if one reads the Bible through the eyes of the marginalized, the poor, and the oppressed, then that will guide our political behavior.

The most Moltmannian moment in scripture is the cry from the cross  in Mark 15.34: “Eloi eloi lama sabachthani” [My God, my God, why have you forsaken me]. This event is very critical in Moltmann’s theology. In his book, The Crucified God, Moltmann says:

Either Jesus who was abandoned by God is the end of all theology or he is the beginning of a specifically Christian, and therefore critical and liberating, theology of life.

The crux of Moltmann’s theology is the dialectical tension between the cross and resurrection. Luther stressed the concept of Christ becoming our sin on the cross and transferring his righteousness to us, whereas Moltmann sees the cross as an event where Jesus was abandoned by God, and suffered in his divinity.

This raises another difference (of many) between Moltmann and Luther, as the former finds Chalcedonian Christology and a thomistic view of God to be unhelpful and ultimately wrong. Moltmann holds to a panentheistic view of God and he sees God as being complete only when all of creation is perfected. Also, while Luther sees God in the classical sense of a being, Moltmann also sees God as an event. Moltmann says in The Crucified God:

‘God’ is not another nature or a heavenly person or a moral authority, but in fact an ‘event’. However, it is not the event of co-humanity, but the event of Golgotha, the event of the love of the Son and the grief of the Father from which the Spirit who opens up the future and creates life in fact derives.