大般涅槃經集解 2.51

2.51

案僧亮曰：此言不生。生是苦本，惑是生因。羅漢斷三界之惑，苦果不生，故名不生也。僧宗曰：此名含三義。一謂殺賊，蓋斷煩惱也；二謂不生，蓋不受三界生也；三謂應供。以備三德，可為福田也。

Sengliang states: This means non-arising. Arising is the root of suffering, and delusion is the cause of arising. Arhats have severed the delusions of the three realms, and the fruit of suffering does not arise; hence it is called non-arising.
Sengzong states: This name contains three meanings: first, slayer of foes, which means severing afflictions; second, non-arising, which means not receiving birth in the three realms; third, worthy of offerings. Because they are endowed with the three virtues, they can be fields of merit.