大毘盧遮那成佛經疏 13.52

13.52

又此索者從何而生？謂從如來信解中生。信解義，如經卷初已說。如來以此信解之力，普門示現種種類形，或作大忿怒事，或為持明之仙，具大力勢，折伏攝受無量眾生，咸令獲於如來妙果，即是大索廣普同有情界義也。

Furthermore, from what is this noose born? It is born from the Tathāgata's resolute faith (adhimukti). The meaning of resolute faith has already been explained at the beginning of the sūtra fascicle. By the power of this resolute faith, the Tathāgata manifests various kinds of forms through universal gateways: sometimes performing great wrathful deeds, sometimes becoming a vidyādhara ṛṣi endowed with great power and might, subduing and gathering in immeasurable sentient beings, causing them all to obtain the Tathāgata's wondrous fruit. This is the meaning of the great noose universally pervading the realm of sentient beings.