Recent comments by Danny Nahlia from Catch the Fire on the QLD floods and God's judgment made this an obvious quote to put up - with thanks to John Alchin.
Exclusion and Embrace by Miroslav Volf
Without entrusting oneself to the God who judges justly, it will hardly be possible to follow the crucified Messiah and refuse to retaliate when abused. The certainty of God's just judgment at the end of history is the presupposition for the renunciation of violence in the middle of it. The divine system of judgment is not the flip side of the human reign of terror, but a necessary correlate of human nonviolence. (p.302)