“In dependence upon suffering, you are able to accumulate the merit that is necessary to produce permanent happiness and liberation. If you examine the life stories and examples of the past saints and mahasiddhas, as well as the Jataka accounts of previous lives of Buddha Shakyamuni, you can clearly see how true practitioners dedicated their lives toward this pursuit – such as the example of Lord Buddha’s past life when he was in Nepal and offered his body to the dying tigress and her cubs at the spot called “Namo Buddha.”
First you must train. It’s like getting ready to go into combat. The army has to train from the very first day in order to know how to handle the actual moment of combat. You are practitioners on the path; and, as spiritual warriors, you are preparing for your time of death. If you get these methods down now, then the transition will be something you can easily face. You will be well prepared.
There are some who use adversity as the support for training in the development of renunciation. This is done by recognizing that, as long as you wander without any self-control in cyclic existence, the occurrence of this type of adversity is not an injustice that’s being imposed upon you. It’s not something that is unfair. Rather, it is the play of the very nature of cyclic existence itself. Furthermore, while you are basically happy with this precious human rebirth, if it is difficult for you to bear such minor adversity now when you are in what is considered to be a fortunate rebirth, just imagine how very difficult it will be for you to endure the suffering of the lower realms. What would it be like if one were reborn in the lower realms where the suffering is truly unbearable?
Notice then that, if you are not able to be patient or to endure the small distress and misery that occurs now, you will not be able to endure it in the lower realms. Right now is the time to make sure that you do not have to endure the suffering of the lower realms.”
from “Meditation, Transformation, and Dream Yoga” by Gyatrul Rinpoche, B. Alan Wallace, Sangye Khandro