大乘起信論別記 1.80

1.80

「因熏習」者，此性功德能作正因熏眾生心，能起厭樂及諸加行，乃至佛果，言因熏習。一切諸法悉於中現，故名為鏡。如《花嚴》云「譬如深大海，彌寶不可盡，於中悉顯現，眾生形類像。甚深因緣海，功德寶無盡，清淨法身中，無像而不顯。」正謂此也。

As for the "perfuming of the cause," these nature qualities can act as a direct cause to perfume the minds of sentient beings, being able to give rise to revulsion [toward saṃsāra], delight [in nirvāṇa], and various preparations, up to the fruit of Buddhahood; hence it is called the perfuming of the cause. Because all dharmas are fully manifested within it, it is named a mirror. As the Avataṃsakasūtra says: "Like the deep ocean / Filled endlessly with treasures, / Within which are fully manifested / The forms and images of sentient beings; / The ocean of profound causes and conditions / Has an inexhaustible treasure of virtues; / In the pure dharmakāya, / There is no image that does not appear." It refers precisely to this.