pūrvayogaparivartaḥ
pūrvayoga – Prior Connection, from pūrva, prior, previous, former, and yoga, connection. That is to say, either yoga or practice in the past, or a connection of the present discourse to past events, i.e. a story of former existences.
The goal is so remote and distant, so the buddhas devise the skilful means of the three vehicles. Also, this way of teaching was used in the past.
The Buddha relates a story from the past:
The past Buddha Mahābhijñājñānābhibhū (Greatly Victorious in the Knowledge of Understanding) attained awakening, which illuminates all directions, including the deva’s palaces. (113-7)
His sixteen sons, their mothers, and all the Brahmas ask why these lights appeared and implore the Buddha to turn the Dharma Wheel. (117-126)
Buddha Mahābhijñājñānābhibhū turns the Dharma Wheel thrice:
He teaches the Four Noble Truths. (127)
He teaches the Twelve Links of Dependent Origination, which awakens many beings. (127-8)
He then teaches the Lotus Sūtra, which leads many more beings to full buddhahood. (128-130)
His sixteenth son was Śākyamuni Buddha. (130)
The Buddha explains, using another parable, why there is only the One Vehicle:
A guide is leading travellers to buried treasure. (131)
The travellers weary and want to turn back. (131)
The guide conjures up an apparitional city, which convinces the travellers to continue to that spot and rest. (131)
When they finished resting, the guide reveals that the city was illusory and only an expedient for getting them to continue. (132)
This is just why the buddhas teach the three vehicles, to lead beings to the goal of the One Vehicle. (132)
The teaching is summarised in verse form. (132-8)
Chapter Six gave us examples of predictions to future Buddhahood of the four great disciples. We know, however, that this teaching is also conventional: ultimately, the reason the Buddha gave predictions is here easily likened to the apparitional city. The goal is beyond description and ineffable, so it cannot be described as a “Buddha Land,” and yet, beings are described as attaining awakening and having Buddha Lands in the future, and in this chapter, they are described as attaining awakening in the past.