We want to avoid taking rebirth in one of the lower realms in the future. The suffering in the animal, hungry ghost and hell realms is far worse than what we endure in this human life. We also have no chance to make spiritual progress in those rebirths, as our suffering will be too great to bear. Negative karma causes us to take rebirth in the animal realm, heavier negative karma will cause us to end up in the hungry ghost realm and the heaviest negative karma we engage in will cause us to be born in hell. It is very easy for us to gain negative karma in this very lifetime. Simply squatting a mosquito in anger can create the cause to be reborn in hell. In this life and all our previous lives we have done many bad actions. We know this is true because of the difficulties we go through in our lives now. We need to do our best to change our impulses to behave badly, so we do not give ourselves even more negative karma. We can meditate to make our mind familiar with the danger of doing...