It may be doubtful, at first, whether a person is an enemy or friend. Meat, if not properly digested, becomes poison; But poison, if used rightly, may turn medicinal. ↗
We learn our virtues from our friends who love us; our faults from the enemy who hates us. We cannot easily discover our real character from a friend. He is a mirror, on which the warmth of our breath impedes the clearness of the reflection. ↗