俱舍論疏 1.274

1.274

論「自身名內至或約處辨」，自身名內者，自身名內，他身及非有情名外。若就處釋內外，五根名內，五境名外。

The treatise says: "One's own body is called internal... or differentiated in terms of bases." 'One's own body is called internal' means that one's own body is called internal, while other bodies and non-sentient things are called external. If explaining internal and external in terms of bases, the five faculties are called internal, and the five sense-objects are called external.