俱舍論頌疏論本 11.76

11.76

無色壽量從下如次二、四、六、八萬大劫，謂空處二萬劫，識處四萬劫，無所有處六萬劫，非想非非想八萬大劫，應知如上所說劫量。少光已上大全為劫，八十中劫為一劫也。自此下諸天大半為劫，四十中劫為一劫也。由此理故，經說大梵過梵輔天壽一劫半，謂以成、住、壞各二十中劫，此六十中劫為一劫半，故以大半四十中劫為下三天所壽劫量。言三天者，梵眾、梵輔、大梵天也。

The lifespan in the formless [realm], ascending from below, is in order twenty, forty, sixty, and eighty thousand great kalpas: that is, the Sphere of Infinite Space is twenty thousand kalpas, the Sphere of Infinite Consciousness is forty thousand kalpas, the Sphere of Nothingness is sixty thousand kalpas, and Neither-Perception-Nor-Non-Perception is eighty thousand great kalpas. One should know the measure of the kalpas as explained above. From Parīttābha upward, a full great [kalpa] counts as a kalpa—eighty intermediate kalpas constitute one kalpa. For the gods below this, half a great [kalpa] counts as a kalpa—forty intermediate kalpas constitute one kalpa. By this reasoning, the sūtra states that Mahābrahmā exceeds the lifespan of the Brahmapurohita gods by one and a half kalpas: taking the twenty intermediate kalpas of each of formation, duration, and destruction, these sixty intermediate kalpas constitute one and a half kalpas; thus, half a great [kalpa] of forty intermediate kalpas is the kalpa measure of life for the lower three heavens. 'The three heavens' refers to the Brahmakāyika, Brahmapurohita, and Mahābrahmā heavens.