On 1 June 1934 he signed the Barmen Declaration, the foundational manifesto of the Confessing Church – it proclaimed that Christian belief and National Socialism were incompatible, and condemned pro-Nazi German Christianity as "false teaching", or heresy. Bell reported on 6 June to a gathering of the bishops of the Church of England and clarified the difference between confessing and rejecting, and the separation between a lawful and an illegitimate calling on Jesus Christ. This was the first reaction to the Declaration from the international church.