大方廣佛華嚴經疏 1.12

1.12

Fourth, to serve as the root of the teachings: without the ocean, there would be no subterranean streams; without the trunk, there would be no branches spreading out. Wishing to gradually dispense branch teachings in accordance with capacity, he first revealed the root Dharma by suddenly expounding this sūtra. But this also has two meanings: First, to be the root for opening the gradual. The 'Manifestation Chapter' says: 'Just as the rising sun first illuminates the high mountains.' Second, to be the root for gathering the branches. 'Just as the setting sun again illuminates the high mountains,' and 'There is nothing that does not flow forth from this dharmadhātu, and nothing that does not return to this dharmadhātu.' The Lotus Sūtra also says: 'When they first saw my body and heard what I taught, they all immediately believed and accepted it, entering into the Tathāgata's wisdom.' This refers to the root of the gradual. Next, it says: 'Except for those who had previously cultivated and studied the Hīnayāna,' which refers to opening the gradual. It also says: 'Now I also cause them to hear this sūtra and enter into the Buddha's wisdom,' which refers to gathering the branches back to the root. Thus the Lotus Sūtra also points to this sūtra as the root.