俱舍論記 8.88

8.88

「下三無色至是名為七」者，此釋第四、第五句。四無色中取下三種，謂空無邊處天是第五識住，識無邊處天是第六識住，無所有處天是第七識住，是名為七。

"The lower three formless […] these are named the seven": this explains the fourth and fifth lines. Among the four formless [realms], it takes the lower three: the heaven of the base of infinite space is the fifth abode of consciousness; the heaven of the base of infinite consciousness is the sixth abode of consciousness; and the heaven of the base of nothingness is the seventh abode of consciousness. These are named the seven.