俱舍論記 24.153

24.153

「論曰至依三界身」者，釋第一句。於四果中，前三但依欲界身得，得阿羅漢通依三界身也。

Regarding "The treatise says ... relying on an embodiment in the three realms": this explains the first line. Among the four fruits, the first three are attained only relying on an embodiment in the desire realm, whereas attaining arhatship is common to relying on embodiments across all three realms.