俱舍論疏 2.95

2.95

論「聲有等流至隨欲轉故」，釋聲唯通二類。飲食等長養，生故有長養。離長養有等流，故有別等流。異熟色法一起相續，聲隨欲生故非異熟，是有為故。非實從同類因生，故非剎那。

The Śāstra states: "Sound has [the categories of] outflowing... because it operates in accordance with desire." This explains that sound only extends to two categories. Generated by nutritional augmentation such as food and drink, it therefore has nutritional augmentation. Apart from nutritional augmentation, there is outflowing; therefore, there is a distinct outflowing. Maturation rūpa dharmas, once arising, form a continuum; sound arises in accordance with desire, and therefore is not maturation, because it is conditioned. It is not truly produced from a cause of the same kind, and therefore is not momentary.