When we look at a fly buzzing around, we train ourselves to think, "My enlightenment depends on that fly." This isn't fanciful thinking because, in fact, our enlightenment does depend on that fly. If that fly isn't included in our bodhicitta, then we don't have bodhicitta, and we won't receive the wonderful results of generating bodhicitta — the tremendous purification and creation of positive potential. Imagine training your mind so that when you look at every single living being, you think, "My enlightenment depends on that being. The drunk who just got on the bus — my enlightenment depends on him. The soldier in Iraq — my enlightenment depends on him. My brothers and sisters, the teller at the bank, the janitor at my workplace, the president of the United States, the suicide bombers in the Middle East, the slug in my garden, my eighth-grade boyfriend, the babysitter when I was a kid — my enlightenment depends on each of them." All sentient beings are actually that precious to us.

Thubten Chodron, Cultivating a Compassionate Heart