I have snitched this quote from Sacred Threshold who seems to have got it from inward/outward. It is from Henri Nouwen.
You are Christian only so long as you constantly pose critical questions to the society you live in, so long as you emphasize the need of conversion both for yourself and for the world, so long as you in no way let yourself become established in the situation of the world, so long as you stay unsatisfied with the status quo and keep saying that a new world is yet to come. You are Christian only when you believe you have a role to play in the realization of the new kingdom, and when you urge everyone you meet with holy unrest to make haste so that the promise might soon be fulfilled. So long as you live as a Christian you keep looking for a new order, a new structure, a new life.
When you can do nothing else: bear witness.