俱舍論記 10.177

10.177

「又部多者至說名求生」者，第二釋。言部多者，是無生義，謂阿羅漢不受生故。部多言含多義，故存梵音。餘凡夫、有學諸有愛者說名求生，更受生故。

Regarding 'Furthermore, "beings" [...] are designated "those seeking rebirth"': This is the second explanation. The term *bhūta* has the meaning of 'non-birth', meaning that the arhat does not undergo rebirth. Because the word *bhūta* contains multiple meanings, the Sanskrit sound is preserved. The remaining ordinary beings, those in training, and all who possess craving for existence are designated 'those seeking rebirth', because they will undergo rebirth again.