俱舍論頌疏論本 10.45

10.45

二緣欲十二者，二謂初禪、二禪，此初、二禪唯繫十二，謂六喜六捨，但除六憂，彼無憂故。緣欲界境共亦有十二，除六憂境也。

Regarding "the two [dhyānas] have twelve cognizing the desire [realm]": "the two" means the first dhyāna and the second dhyāna. These first and second dhyānas are bound to only twelve: namely, six of joy and six of equanimity, only excluding the six of grief, because that realm lacks grief. In cognizing objects of the desire realm, there are also twelve in total, excluding the six grief objects.