The more I thought about this, the more I realised that it's so much easier for me to live reactively, defensively, defending-ly (as Peter did) than to adopt the proactive, giving, accepting way of Jesus.
Then I read today's entry over at Living Wittily and was struck by this section from Elizabeth Jennings poem:
"Teach me how you love and have to die
And I will try
Somehow to forget myself and give
Life and joy so dead things start to live."
With help, we can make positive choices, even though we are aware of our own intrinsic frailty. I guess that in many ways it's about demonstrating the difference between knowing Jesus and knowing about him.