That means being constantly restless - looking for more Kingdom-likeness, anticipating what to many will seem to be an 'other-world' or 'out of this world' viewpoint. Not so that we are of no practical use in the today, but precisely because we have this other-world view we are down to earth and head-strong in the belief that things today can be changed.
Nouwen puts it well in his book Open Hands:
You are Christian only so long as ...
- you look forward to a new world
- you pose critical questions to society of today
- you emphasize the need for conversion
- you do not let yourself become established in seeming calm
- you stay unsatisfied with the status quo
- you keep saying that a new world is yet to come
- you believe you have a role to play in realising this new kingdom
- you urge everyone with a holy unrest to make haste
So if you follow Christ, then be Christian ... be restless.