The teaching of “impermanence” is a key teaching in Vajrayana Buddhism, which is repeatedly stressed by all the Khenpos and Rinpoches, regardless of their sects and the level of practice. They have been practicing for a long time, at least for ten to twenty years, but their teachers would continue to stress the importance of the teaching of “impermanence” throughout their training. The same teaching would be repeated in many ways, in any assembly and in any discourse, in order to make them feel very deeply about the impermanence of life. As long as you have not developed a sense of impermanence in you, you will be easily influenced by worldly enjoyments, and a sense of love and hatred which will perpetually bind you to the cyclic existence (samsara). Actually, what they are trying to say is that life is impermanent, and we can die anytime and very soon. So, we should strive to break free from such cyclical deaths. When you truly feel the urgency of death, you will develop a sense of renunciation swiftly and lose your interest in all the worldly concerns; this will make you focus all your energy on the practice leading to the ultimate freedom.
Gunga Wangchok Lama gave a lot of teachings in his life and he had groomed many Khenpos. In one of his books, he cited a phenomenon in the cyclic existence - “In the human world, one's father could become his son and one's mother could become his wife.” A father could be reborn as a son to his own son. A mother could be reborn as a wife to her own son. Also, “One's enemy could become his close relative.” Your enemy from previous life could be reborn as your family member and create trouble for you. Cyclic existence, as its name suggests, never ends. We are clueless of who will become who next? This is how we go through the endless cycles of birth and death. When we obtain a human birth again, we might bump into our late father who has become our child etc. Sakyamuni Buddha told his students that sometimes, your father in this life would become your son in his next life; your son in this life would become your father in your next life; your mother in this life would become your wife in her next life; and your wife would become your enemy in her next life. The roles keep changing and they will never remain the same.
During the time of Sakyamuni Buddha, there was an Arahat by the name of Jia-tuo-yan, who went around for alms one day. He came across a house where he saw a woman eating pork while holding a baby in her arm and breast feeding him. There was a dog right in front of her house which was waiting for a chance to eat a bit of the gravy from the meat that she was eating. Later, that woman threw a piece of bone at the dog after finishing the meat. Sakyamuni Buddha told the Arahat, “Do you know that the meat eaten by that woman came from a pig that was the rebirth of her late father? Her father fell into the animal realm. The baby who was sucking her milk was the enemy who killed her husband; she was feeding him with her milk now and loved him so much. Her mother was reborn as a dog because of her own negative karma. Now, the daughter threw a piece of bone on the face of her late mother (the dog), and the mother was chewing the bone of her former husband (the pig). Her late mother was reborn as a dog and her late father was reborn as a pig. The Arahat, after witnessing the phenomenon realized that all the worldly relationships are but transient; he developed a very strong sense of renunciation as a result.
Many students developed a sense of renunciation after hearing this strange phenomenon from Sakyamuni Buddha. They found cyclic existence absolutely meaningless for one’s father, son, student, spouse etc. are just transient relationships that will continue to change and one is just going round and round a circle. The Arahat developed a sense of renunciation and completely lost his attachment to the Three Realms (Desire Realm, Realm of Form and Formless Realm) thence. What Sakyamuni Buddha was trying to do was to break our attachment to this life, especially our attachment to our family. As long as you love your children, your parents etc., you are actually blinded by the superficial value of cyclic existence, which is very scary.
Sakyamuni Buddha also mentioned about the Heaven Realm. The heavenly beings enjoyed great fortunes in heaven but they would fall into hell and suffer great hardships when their merits are exhausted. This is real. Heavenly beings enjoyed great sensual pleasures in heaven and they live a very long life that could last for thousands of years, equivalent to millions of years in the Human Realm. They could touch the beautiful breasts of the female heavenly beings and enjoyed the sense of touch. They could also touch the slim waist of the female heavenly beings and enjoyed the sense of touch. However, when their merits are exhausted, they will plunge straight into two gigantic iron mountains in hell. Their bodies will be scotched by the fire of hell and cut into pieces by iron birds. The iron birds will cut away your eyes, your nose, your mouth and your tongue; you will feel the greatest pain and misery in hell. These are inconceivable fruits of negative karma in hell. One enjoyed inconceivable sensual pleasures in heaven and went through inconceivable pains in hell next. In the human world, your relatives and friends will have their roles change from life to life…… Therefore, Sakyamuni Buddha kept telling us about the impermanence of life, and that we should break free from this cyclic existence, and break free from sufferings. When we realize that the human world is full of sufferings, we should turn towards the teachings of the Buddha and put them into practice. Only through practice, we can eventually break free from the cyclic existence.
A Dharma discourse given by Acho Rinpoche on 29 Jun 2013