"it is only when God's wrath and vengeance are hanging as grim realities over the heads of one's enemies that something of what it means to love and forgive them can touch our hearts"
This thought brings a whole new perspective on Jesus teaching to love your enemy (Matthew 5:44).
I think that most people apply this instruction in a passive way, interpreting love your enemy to mean in practice, leave each other in peace. This requires very little of us other than not to be a protagonist against those we consider 'against us'.
Since being challenged by Bonhoeffer to consider the reality of the future awaiting my enemies, I have thought much more about what it means to really love an enemy. Surely it has to be an active response requiring me to overcome any enmity between us, to foster reconciliation and to practice love, much like I would when applying 'love thy neighbour'.
As a believer who has acknowledged the 'hell' that would be an eternity apart from the presence of God, I would not consider that an appropriate future for any man, if given the opportunity to respond to the gospel of grace from our God.
I'm not convinced that I can currently think of anybody who I personally consider an enemy but there are social, cultural, religious (even world) contexts where as Christians we appear (appearances can be deceptive depending on where you stand) in opposition to many others. Are these our enemies? Do our opponents consider us as enemies? Either way our response should be love and more than just the thought of it.
It is too soon for me to work out all of the practicalities of what this might look like in my everyday life but it does cause you to pray.
The most challenging thing for me from this train of thought is if this causes a change in my approach to my enemies, how much more does it apply to those who I love who don't yet know Jesus?