The Swiss theologian Karl Barth has been called the most outstanding and consequently evangelical theologian of modern times. Pope Pius XII (1876-1958) Barth called the most important theologian since Thomas Aquinas. From whatever perspective you see him: Karl Barth has had a profound influence on modern Christian church leaders and scholars from many different traditions.
Apprenticeship and crisis of faith
Barth was born on May 10, 1886, at the height of the influence of liberal theology in Europe. He was a pupil and disciple of Wilhelm Herrmann (1846-1922), a leading representative of the so-called anthropological theology, which is based on personal experience of God. Barth wrote about him: Herrmann was the theological teacher of my student days. In these early years Barth also followed the teachings of the German theologian Friedrich Schleiermacher (1768-1834), the father of modern theology. I was inclined to give him fide implicita across the board, he wrote. 
1911-1921 Barth worked as a pastor of the Reformed community of Safenwil in Switzerland. A manifesto in which 93 German intellectuals spoke out for the war aims of Kaiser Wilhelm II shook 1914 his liberal faith building in August in the foundations. Barth's liberal theology professors were also among the signatories. With that came a whole world of exegesis, ethics, dogmatics, and preaching, which until then I had believed to be fundamentally credible ... to the point of failure, he said.
Barth believed his teachers had betrayed the Christian faith. By transforming the gospel into a statement, a religion, over the self-understanding of the Christian, one has lost sight of the God who, in his sovereignty, confronts man, demands an account from him, and acts on him as master.
Eduard Thurneysen (1888-1974), pastor of a neighboring village and Barth's close friend from his student days, experienced a similar crisis of faith. One day Thurneysen whispered to Barth: What we need for preaching, teaching and pastoral care is a 'completely different' theological foundation. 
Together, they struggled for a new basis for Christian theology. It was necessary to re-use the theological ABC once again and more contemplatively than before by reading and interpreting the writings of the Old Testament and the New Testament. Lo and behold, they started talking to us ...  A return to the origins of the gospel was necessary. It was necessary to start again with a new inner orientation and to recognize God as God again.
Romans and ecclesiastical dogmatics
1919 released Barth's seminal commentary The Letter to the Romans and got 1922 a complete rewrite for a reissue. His revised Epistle to the Romans sketched out a bold new theological system in which God quite simply meant in his independence of man, and to behold. 
In the letter of Paul and in other biblical writings Barth found a new world. A world in which it was no longer the right thoughts of man about God, but the right thoughts of God above men became visible.  Barth declared God to be radically different, beyond our understanding, which remains bent on us, that is alien to our senses and recognizable only in Christ. God's rightly understood divinity includes: his humanity.  Theology must be doctrine of God and man. 
1921 became Barth Professor of Reformed Theology in Göttingen, where he taught until 1925. His core area was dogmatics, which he considered a reflection on the Word of God as revelation, hl. Scripture and Christian preaching ... defined the actual Christian sermon. 
1925 he was appointed Professor of Dogmatics and New Testament Exegesis in Münster and five years later to the Chair of Systematic Theology to Bonn, which he held until 1935.
1932 he published the first part of the Church Dogmatics. The new work grew year by year from its lectures.
Dogmatics has four parts: The teaching of the Word of God (KD I), The Doctrine of God (KD II), The Doctrine of Creation (KD III) and The Doctrine of Reconciliation (KD IV). The parts each comprise several volumes. Barth originally designed the work in five parts. He could no longer complete the part on reconciliation, and the part on redemption remained unwritten after his death.
Thomas F. Torrance calls Barth's dogmatics by far the most original and noteworthy contribution to the systematic theology of modernity. KD II, part 1 and 2, especially the doctrine of God's being in fact and God's doing in his being, he considers the culmination of Barth's dogmatics. In Torrance's eyes, KD IV is the most powerful work ever written on Atonement and Reconciliation.
Christ: Elected and Elect
Barth subjected the entire Christian doctrine to radical criticism and reinterpretation in the light of the Incarnation. He wrote: My new task was to rethink and pronounce everything that was said before, that is, now as a theology of the grace of God in Jesus Christ.  Barth sought to locate the Christian preaching as an activity that proclaims the powerful action of God and not the actions and words of men.
Christ is at the center of dogmatics from beginning to end. Karl Barth was a Christian theologian who was primarily concerned with the uniqueness and centrality of Christ and his gospel (Torrance). Barth: If you miss each other here, you missed the whole.  This approach and rooting in Christ saved him from falling into the trap of natural theology, which ascribes legitimate authority over the message and form of the Church to man.
Barth insisted that Christ is the revelatory and reconciling agency through which God speaks to man; in Torrance's words, the place where we recognize the Father. God is known only through God, Barth used to say.  A statement about God is true if it is in harmony with Christ; between God and man is the person of Jesus Christ, even God and even man, who mediates between them. In Christ, God reveals himself to man; in him see and he knows God.
In his doctrine of predestination, Barth proceeded from the election of Christ in a twofold sense: Christ as chosen and electing at the same time. Jesus is not only the God who chooses but also the chosen man. Therefore,  election has to do exclusively with Christ, whose election we, chosen by him, share. In the light of the election of man, according to Barth, all election can only be described as free grace.
Before and after the Second World War
Barth's years in Bonn coincided with the rise and seizure of power by Adolf Hitler. A National Socialist church movement, the German Christians, sought to legitimize the leader as a God-sent savior.
In April 1933 the German Evangelical Church was founded with the aim of promoting the German ethos about race, blood and soil, people and the state (Barth) as a second foundation and source of revelation for the Church. The Confessing Church emerged as a counter-movement, which rejected this nationalist and human-centered ideology. Barth was one of her leading figures.
In May 1934 she published the famous Barmen Theological Declaration, which is mostly by Barth and reflects his Christ-related theology. In six articles, the Declaration calls on the Church to focus exclusively on Christ's revelation and not on human powers and powers. Outside of the one word of God, there is no other source for the church proclamation.
In November 1934 Barth lost the teaching license in Bonn, after he had refused to sign an unconditional oath of allegiance to Adolf Hitler. Formally dismissed from 1935 in June, he immediately received a call to Switzerland as a professor of theology in Basel, a position he held until his retirement 1962.
1946, after the war, Barth was invited back to Bonn, where he held a published in the following year as dogmatics in the demolition lecture series. Built according to the Apostles' Creed, the book deals with topics that Barth had developed in his voluminous ecclesiastical dogmatics.
1962 visited Barth USA and lectured at Princeton Theological Seminary and the University of Chicago. When asked to give a brief formula to the theological meaning of the millions of words of the Church Dogmatics, he was to think for a moment and then say:
Jesus loves me, that's for sure. Because it makes the script recognizable. Whether the quote is authentic or not: Barth often answered questions. It expresses his basic belief that at the heart of the gospel is a simple message that points to Christ as our Savior, who loves us with perfect divine love.
Barth understood his revolutionary dogmatic not as the last word in theology, but as the opening of a new common debate.  Modestly, he does not necessarily acknowledge his work of eternal value: Somewhere on a heavenly screed, at some point in time, he will also be able to deposit the church dogmatic ... into a waste paper.  In his last lectures, he concludes that his theological insights will lead to a rethink in the future, for the Church is required to start again at zero point every day, even every hour.
On the 12. December 1968 Karl Barth, aged 82 years old, died in Basel.
by Paul Kroll
Karl Barth, The Humanity of God. Biel 1956
Karl Barth, Church Dogmatic. Vol. I / 1. Zollikon, Zurich 1952 ditto, Vol. II
Karl Barth, The Letter to the Romans. 1st version. Zurich 1985 (as part of the Barth Complete Edition)
Karl Barth, Dogmatics in outline. Munich 1947
Eberhard Busch, Karl Barth's CV. Munich 1978
Thomas F. Torrance, Karl Barth: Biblical and Evangelical Theologican. T. & T. Clark 1991
1 Busch, p. 56
2 Busch, p. 52
3 Romans, Preface, p. IX
4 Busch, p. 120
5 Busch, p. 131-132
6 Busch, p. 114
7 Busch, p. 439
8 Busch, p. 440
9 Busch, p. 168
10 Busch, p. 223
11 Busch, p. 393
12 bush, passim
13 Busch, p. 315
14 Busch, p. 506
15 Busch, p. 507