"If we could read the secret history of our enemies we should find in each man's life sorrow and suffering enough to disarm all hostility"

This quote by Henry Wadsworth Longfellow talks to the idea that if we were to check out the lives of our opponents, we would discover that they too have actually experienced sorrow and suffering. This understanding of our enemies would, in turn, deactivate any hostility we may have towards them. Longfellow is recommending that we ought to not be so quick to judge or be hostile towards those we consider our enemies, as we do not know what they have actually gone through in their lives. He is recommending that we need to take an action back and attempt to comprehend our enemies, rather than immediately reacting with hostility. Longfellow is motivating us to be more thoughtful and understanding of our enemies, and to acknowledge that all of us have our own battles and griefs. He is recommending that if we make the effort to comprehend our opponents, we may be able to find common ground and put aside our differences.