Tolerance kills us.
I haven't read enough Hauerwas to know what he might mean by this, but Slavoj Zizek offers some clues:
Tolerance means don't harass me; don't harass me means come too close to me....In other words, tolerance means I am intolerant to your over-proximity to me. Tolerance means don't come too close; stay at the proper distance.
Tolerance is distance. Distance is loneliness. And loneliness kills us.