俱舍論記 28.46

28.46

「若謂觀下至彼界無色」者，又牒救破。若謂無色觀下欲、色界麁色故，說超色想等。則於段食亦應許然，應超下麁段食有細段食。又四靜慮超下麁色，亦應可說出離色言，是則四靜慮亦應名無色。又亦應說無色界中出離受等，彼亦超下麁受等故。經既不說無色界中超受等言，知無色中遍超色類非超受等。由此定知彼界無色。

Regarding 'If it is claimed that with respect to lower... that realm has no form': this again takes up their defense and refutes it. If you claim that it is with respect to the coarse forms of the lower desire and form realms that the text speaks of 'transcending ideations of form' and so forth, then the same should be granted for material food: having transcended lower coarse material food, there should be subtle material food. Furthermore, the four dhyānas transcend lower coarse form, so the words 'emancipation from form' should also apply to them; if so, the four dhyānas should also be called 'formless'. Furthermore, one should also speak of 'emancipation from feeling' and the like in the formless realm, because they also transcend lower coarse feeling and the like. Since the sūtra does not speak of transcending feeling and the like in the formless realm, we know that in the formless realm there is a comprehensive transcendence of the class of form, not a transcendence of feeling and the like. From this, it is definitively known that that realm has no form.