瑜伽論記 17.555

17.555

下明受俱轉相。言又諸轉識至俱有而轉者，或有六轉識並同生樂受，以三受解義竟，地喜受亦名為樂。

Below, explaining the characteristics of the co-arising operation of feelings. Regarding the statement, "Furthermore, the operating consciousnesses […] operate co-existently": sometimes the six operating consciousnesses all simultaneously generate pleasant feeling. Having completely explained the meaning through the three feelings, the joy of the [meditative] stages is also called pleasure.