俱舍論記 27.123

27.123

「此二界化至故總成八」者，釋後兩句。此二界化各有二種，謂欲界中化，屬自身、他身別故；謂色界中化，屬自身、他身別故。身在欲界化有四種，欲界自身、他身化，色界自身、他身化身。在色界化亦有四，色界自身、他身化，欲界自身、他身化。故總成八。

On "The transformations of these two realms ... thus in total making eight": this explains the last two lines. The transformations of these two realms each have two kinds: that is, transformations in the desire realm are differentiated into those belonging to one's own body and another's body; and transformations in the form realm are differentiated into those belonging to one's own body and another's body. When the body is in the desire realm, there are four kinds of transformation: desire-realm transformations of one's own body and another's body, and form-realm transformations of one's own body and another's body. When the body is in the form realm, there are also four: form-realm transformations of one's own body and another's body, and desire-realm transformations of one's own body and another's body. Therefore, in total they make eight.