Day 21 covers all of Chapter 16, The Duration of the Life of the Tathāgata.
Having last month considered the skillfull physician and what happened while he was away, we consider the medicine and the unwillingness of some sons to take the medicine.
“The father thought, ‘These sons are pitiful. They are so poisoned that they are perverted. Although they rejoice at seeing me and ask me to cure them, they do not consent to take this good medicine. Now I will have them take it with an expedient.’
“He said to them, ‘Know this! Now I am old and decrepit. I shall die soon. lam leaving this good medicine here. Take it! Do not be afraid that you will not be cured!’ Having thus advised them, he went to a [remote] country again. Then he sent home a messenger to tell them, ‘Your father has just died.’
“Having heard that their father had passed away from this world, leaving them behind, they felt extremely sorry. They thought, ‘If our father were alive, he would love and protect us. Now he has
deserted us and died in a remote country.’“They felt lonely and helpless because they thought that they were parentless and shelterless. Their constant sadness finally caused them to recover their right minds. They realized that the medicine had a good color, smell and taste. They took it and were completely cured of the poison. On hearing that they had recovered their health, the father returned home, and showed himself to them.
“Good men! What do you think of this? Do you think that anyone can accuse this excellent physician of falsehood?”
“No, World-Honored One!”
The Buddha said:
“I am like the father. It is many hundreds of thousands of billions of nayutas of asaṃkhyas of kalpas since I became the Buddha. In order to save the [perverted] people, I say expediently, ‘I shall pass away.’ No one will accuse me of falsehood by the [common] law.”