A real understanding of impermanence makes us more tolerant. Suppose we feel like exploding in anger at someone who harms us. If we see the impermanent nature of enmity, we will realize that this person who appears as our enemy today might have been our child in a past life. Tomorrow, they might be our best friend. That thought will let the air of hatred out of our chest. We might also feel the pointlessness and emptiness of fighting with anyone, as beings are constantly changing faces. We could even feel compassionate toward this so-called enemy of ours, for, in the course of time, their efforts to harm us will end up hurting them as they face the consequences.
Excerpted from: Peaceful Death, Joyful Rebirth, Tulku Thondup, Shambhala Publications