瑜伽論記 9.335

9.335

有釋：良以小乘於上地變不能現化故有十四化。今依大乘菩薩神通以自在故依四定一一皆能作五地化，故有二十化，或詳此論，四無色中亦有化心，故過二十數。

There is an explanation: Truly because the Hīnayāna cannot manifest transformations from higher stages, there are fourteen manifestations. Now, according to the Mahāyāna, because the bodhisattva's supernormal powers are sovereign, relying on the four concentrations each is capable of making manifestations of the five stages; therefore there are twenty manifestations. Or, examining this treatise closely, in the four formless realms there are also manifesting minds; hence the number exceeds twenty.