Chih-i quotes passages in the “Chapter On Faith and Understanding” in the Lotus Sūtra concerning the parable about the rich father and his poor son, in order to analogize the Buddha’s teaching in terms of five periods.

1. The passage about the rich father dispatching an attendant to follow his poor son in order to bring him back, and the poor son being terrified, analogizes the Avataṃsaka teaching in the first period that belongs to the Sudden teaching. Chih-i asserts that this is as if from the cow, one extracts fresh milk.
2. The passage about the rich father wishing to entice his son, putting his son to hard work, while disguising himself in dirty clothes as an expedient means in order to approach his son and to keep him at work clearing away dung for twenty years, analogizes the Tripitaka Teaching in the second period that caters to the śrāvakas. Chih-i articulates that this is like from fresh milk, one extracts cream, and from the twelve types of scripture, sūtras are produced.
3. The passage about the poor son at the end of this time gaining confidence in himself, and coming and going without anxiety, though he was lodged in the same place as before, analogizes the Vaipulya teaching in the third period. Chih-i declares that this is like from cream, one extracts curdled milk, and from sūtras, the Vaipulya Sūtras are produced. In this period, the Buddha begins to expound the Greater Vehicle, though the śrāvakas still dwell in the teaching of the Lesser Vehicle.
4. The passage about the rich father telling his son about his treasure houses and his son is conferred to be in charge of the multitude of things, and yet his son had no craving for so much as a single meal, and continued to live as before in the same place, analogizes the Prajn͂āpāramitā teaching in the fourth period. This is like from curdled milk, one extracts butter, and from the Vaipulya Sūtras, the Prajn͂āpāramitāsūtra is produced. Chih-i remarks that the Prajn͂āpāramitā teaching concerns wisdom, and wisdom is treasure.
5. The passage about the rich father declaring the father and son relationship to the multitude, and the poor son being rejoiced and greatly bequeathing all riches of his father which he had never had before, analogizes the Saddharmapuṇḍarīka-Mahāparinirvāṇa teaching in the fifth period. Chih-i articulates that this is like from butter, one extracts ghee, and from the Prajn͂āpāramitāsūtra, the Nirvāṇasūtra is produced. (Vol. 2, Page 456-457)