In the difficult Psalm 137 I notice a song of exiles. This is an angry psalm, coming from an awareness that this world is not a neutral or benign place with everyone trying to do their best. This is a world at war. Given the reality of sin and evil, we live in a world where enemies for believers are a fact of life. Loving enemies, which Jesus calls us to do, presupposes that we notice them and know who they are. Psalms like this remind us of the emotions and suffering that bring notice to us of who our enemies actually are.