This life of continual rise and fall and of continual changes is like running water, and with the running of this water one thinks, "I am this water." In reality one does not know what one is. For instance, if a person goes from poverty to riches, and if those riches are taken away from them, they lament; and one laments because one does not remember that before having those riches one was poor, and from that poverty one came to riches.