俱舍論頌疏論本 20.37

20.37

色自下各三，上一淨識境者，謂色界所繫苦、集、修斷各八識緣，謂自界三及下界三，下即欲界也，三謂前說苦集修斷，並上界一，謂無色界修所斷識能緣色界苦集修故，兼無漏淨識亦緣色界苦集修斷故，此八識一一各皆容緣色界苦集修斷也。

As for 'For the form realm, three each of its own and the lower, one of the higher, and pure consciousness are the domains': what are bound to the form realm and abandoned by suffering, origin, and cultivation are each taken as an object by eight consciousnesses; namely, three of their own realm and three of the lower realm—'lower' meaning the desire realm, and 'three' meaning what are abandoned by suffering, origin, and cultivation as stated above—together with one of the higher realm, meaning the consciousness abandoned by cultivation in the formless realm because it can take the suffering, origin, and cultivation of the form realm as an object, in addition to the uncontaminated pure consciousness also taking what are abandoned by suffering, origin, and cultivation in the form realm as an object. Each of these eight consciousnesses can take what are abandoned by suffering, origin, and cultivation in the form realm as an object.