The Barmen Declaration, 1934, was a call to resistance against the theological claims of the Nazi state. Almost immediately after Hitler's seizure of power in 1933, Protestant Christians faced pressure to "aryanize" the Church, expel Jewish Christians from the ordained ministry and adopt the Nazi "Führer Principle" as the organizing principle of church government. In general, the churches succumbed to these pressures, and some Christians embraced them willingly. The pro-Nazi "German Christian" movement became a force in the church. They glorified Adolf Hitler as a "German prophet" and preached that racial consciousness was a source of revelation alongside the Bible. But many Christians in Germany—including Lutheran and Reformed, liberal and neo-orthodox—opposed the encroachment of Nazi ideology on the Church's proclamation. At Barmen, this emerging "Confessing Church" adopted a declaration drafted by Reformed theologian Karl Barth and Lutheran theologian Hans Asmussen, which expressly repudiated the claim that other powers apart from Christ could be sources of God's revelation. However, Only 10% of the Churches in German signed the Barmen Declaration. We must prepare now so we will be ready then.
There were some heroes would were ready like the Protestant pastor Dietrich Bonhoeffer and the Roman Catholic priest Bernhard Lichtenberg. These two were arrested and executed in concentration camps. The spirituality of the Barmen Declaration profoundly influenced many of the first generation of pastors and laypeople who formed the United Church of Christ in 1957.