大般涅槃經義記 3.37

3.37

'Arhat' is named here 'unattached', because the causes of existence are severed; it is also called 'non-arising', because the fruits of suffering are exhausted. Where is its stage located? In distinction there are three: first, maintaining the fruit, which is on the tenth bhūmi; second, including the cause, from the ninth bhūmi onward they are collectively called arhat; third, advancing toward, extending upward through the vajra[-like concentration]. Combining the latter two, it is called arhat, because these are equally on the ultimate ground. In actual principle, it is the Buddha who is extolling these persons, and thus they share the Buddha's epithet. Since these are all bodhisattvas, why are they named using the designations of śrāvakas and ordinary people? Although these are bodhisattva stages, they broadly correspond to those of the Hīnayāna; in order to cause the ordinary people, two-vehicle persons, and others to be transformed in the future to understand the great by standard of the small, these names are therefore used.