仁王護國般若波羅蜜多經疏 2.248

2.248

解曰：諸佛所說，界外無生。若言界外有眾生界者，即是外道吠世史迦六句義中大有經說，非佛教也。若爾，二乘無學十地菩薩所居報土，豈非界外？答：據隨助緣，即居界外；體是異熟，故非外也。從此第四顯化成佛。

The commentary states: As the Buddhas have taught, there are no sentient beings outside the realms. If one says that outside the realms there is a realm of sentient beings, this is the teaching of the Great Existence Sūtra among the six categories of meaning of the Vaiśeṣika non-Buddhists, not the Buddha's teaching. If so, as for the reward lands inhabited by the non-learners of the two vehicles and the bodhisattvas of the ten bhūmis, are they not outside the realms? Answer: In terms of following auxiliary conditions, they reside outside the realms; but their substance is vipāka, and therefore not outside. From here, the fourth part shows transforming into Buddhahood.