It is very difficult for ordinary sentient beings to conceive of the nirvana of great bodhisattvas like Avalokitesvara and the buddhas. The Mahaprajnaparamita-sastra states, “Nirvana is the state free from all forms—immeasurable and inconceivable, where all thought has ceased. Such are the qualities of nirvana—it is none other than prajnaparamita.”36 ‘No-form,’ ‘immeasurable,’ and ‘no-concept’ are names for prajna as well as nirvana. Bodhisattvas who have reached nirvana are no longer fettered by the chain of samsara or moved by afflictions. Unlike ordinary people who cherish existence in samsara, or arhats who would leave samsara forever, bodhisattvas freely come and go in birth and death. They take setient beings and this world as fields to cultivate their merit. A Buddha is one who has completely finished the task of cultivating this field, and who has perfected his or her merit (compassion) and virtue (wisdom).

To attain anuttara-samyak-sambodhi is the highest realization of the buddhas—anuttara meaning highest, samyak meaning perfect, and sambodhi meaning all-pervasive realization. The word ‘attain’ here should not be misconstrued. The sutra says, "there is no attainment.” In this passage, attainment is that of the fruition of the merit of the buddhas, not that of practicing with the aim of achieving self-liberation.