成唯識論掌中樞要 2.192

2.192

第七識不說初起何界後生，以不定故。若說色界無迴心，初起唯欲界；若說色界有迴心，初起通色界。以定不在，初起法空故，若平等初起在色界身。

Regarding the seventh consciousness, it is not specified in which realm it first arises and later takes birth, because it is not fixed. If one holds that in the form realm there is no turning of the mind, its initial arising is exclusively in the desire realm; if one holds that in the form realm there is turning of the mind, its initial arising pervades the form realm. Because it is not within meditative absorption, its initial arising is dharmā-nairātmya; if [referring to] equality [wisdom], its initial arising is in the body of the form realm.