Jürgen Moltmann (1926-) is a German reformed theologian and professor emeritus of systematic theology at the University of Tübingen.
In his important work, The Crucified God (first released in German in 1972 as Der gekreuzigte Gott. Das Kreuz Christi als Grund und Kritik christlicher Theologie), Moltmann established the crucified Christ as the criterion of all Christian theology. Moltmann, with Luther, affirms that the cross is the test of everything which deserves to be called Christian (‘Crux probat omnia’).
Theological reflection cannot start with abstract, philosophical ideas about God or systematic theories about sin, justice, predestination and so on, but must start with the cross. We know first of all God, not as the omnipotent creator and judge, but as the crucified Christ.
When we let the crucifixion of Christ determine our theological concepts, this has radical and all-embracing consequences for how we view the relationship between God and human beings in general. Moltmann further argues, that putting the crucified Christ in center of Christian faith and theology, is the only way for the church to show the world the freedom from the forces of history and society that Christ offers.
Moltmann’s The Crucified God also anticipates his version of a Christian universalism known from his later book The Coming of God. Moltmann, with Christoph Blumhardt, argues that the cross is “Christianity for all the world”, as the cross dissolves all distinctions between human beings, including those “between Christians and non-Christiand, the pious and the godless” (p. 280).
From the book:
“The cross is not and cannot be loved. Yet only the crucified Christ can bring the freedom which changes the world because it is no longer afraid of death.” (p. xix)
“Whatever can stand before the face of the crucified Christ is true Christian theology. What cannot stand there must disappear.” (p. xii)
“[…]the theology of the cross is the true Christian universalism. There is no distinction here, and there cannot be any more distinctions. All are sinners without distinction, and all will be made righteous without any merit on their part by his grace which has come to pass in Christ Jesus (Rom. 3:24). As the crucified one, the risen Christ is there ‘for all’. In the cross of the Son of God, in his abandonment by God, the ‘crucified’ God is the human God of all godless men and those who have been abandoned by God.” (pp. 279-280)
See also: Jürgen Moltmann: The Coming of God and “The theology of the cross is the true Christian universalism” – Moltmann on the Gentile centurion and Jesus’ Easter appearances