The Kirchentag has to be experienced to be understood. The sheer enormity of scale is mitigated by an organisation that marries efficiency to intimacy. It is estimated that around 300,000 people will come through Hamburg for the Kirchentag in the next three days, but somehow it never feels hassled or crowded.

Unless you don't get to some venues early enough to get in, that is. The was almost a riot outside the enormous hall where Margot Käßmann was doing a Bible Study this morning: the hundreds that couldn't get in to this or the subsequent discussion involving the Federal President, Joachim Gauck, were not happy bunnies.

The Opening Services last night took place in four places. The sun shone on the tens of thousands of people (of all ages) who sang, prayed and listened together. This was followed by the Abend der Begegnung where the city of Hamburg opened its arms in welcome, cultural invitation and generous hospitality.

The theme of the Opening Service on the Rathausmarkt was basically a call for the Church to grow up and take responsibility. There was a particular edge for those of us from Bradford and Wakefield as the preacher spoke of the fusion last year of three Landeskirchen (dioceses) into the single Nordkirche. This new Landeskirche maintains the distinctives not only of regional identity, but also of the three Protestant traditions that make up the Evangelische Kirche in Deutschland (EKD): Lutheran, Reformed and United. The call was clear: stop complaining about change and shape what can be.

And I thought I was coming here to get away from all that…

Anyway, this morning we had to get to our venue an hour early in order to get a seat for just one of the many Bible Studies being led each day. We wanted to hear Margot Käßmann on Luke 18:1-8 – the story of the persistent woman and the unjust judge. 7,000 people; many more unable to get in. Inconceivable in England.

I will put a link up to her text, but she spoke powerfully of the need for persistence in challenging injustice, annoying those who wish to deny justice to the weak and the powerless in society. I can't do justice to her text here, but will cite one – almost incidental – comment she made about a woman called Elisabeth Schmitz (of whom I had never heard.

Elisabeth Schmitz corresponded with the great Protestant theologian Karl Barth between 1933-36, trying to get Barth to engage with the 'Judenfrage' – the fate of the Jews. Barth declined. Theology always has to be read through the prism of history and culture; it never stands alone in some abstract world inhabited by a remote God or a disengaged church. When Schmitz died in 1977 only 7 people attended her funeral – it was only the later discovery of a load of personal documents that gave an indication of the relentless courage of this woman who resisted Hitler and kept a prophetic call alive.

Germany always provides glimpses of people whose integrity is remarkable and whose fearlessness in facing challenge is humbling. Käßmann reiterated the importance of seeing irritating people as 'persistent widows' who compel us to not lose sight of other people's – particularly the weak, the powerless, the abandoned and the refugees – fundamental humanity.