Lectures on the Sūtra of the Collection of the Father and Son (Pitāputrasamāgamanasūtra) (68)

What is the reason we cannot depart from all dharmas? It is because of craving and attachment; having a mind of fondness and delight, the mind abides in all dharmas and cannot be separated from them. Toward all worldly dharmas we wish to possess and own them—this is the mind of fondness and delight. If there is no mind of fondness and delight, the mind will abide nowhere, without wishing to possess or own. In this way the mind is not bound by any dharma, gains the power of liberation, and can attain liberation. For one who does not give rise to fondness and delight toward the desire realm, the first dhyāna concentration arises; for one who has no fondness for the state of the first dhyāna, the state of meditative concentration is raised further; for one who has no fondness even for higher states of meditative concentration, one can reach the highest realm within the three realms; and for one who has no fondness for the dharmas of the three realms of existence, one will enter the cessation of perception and feeling (nirodha-samāpatti), which is the state of an arhat of the fourth fruit. At the end of life, one can extinguish all of one's first seven consciousnesses; when the physical body perishes and the seven consciousnesses are extinguished, and the five aggregates are extinguished, one enters nirvāṇa without remainder (anupadhiśeṣa-nirvāṇa), liberated from birth and death in the three realms, no longer transmigrating.

An arhat can enter nirvāṇa without remainder, ending birth and death and escaping the three realms, precisely because he no longer has any mental action of fondness and delight toward the worldly dharmas of the three realms. We suffer within the three realms, especially within the desire realm; being born in the human world of the desire realm rather than in the heavens of the desire realm is because our mind of fondness and delight toward the dharmas of the desire realm is deeper than that of the devas, deeper still than that of the devas of the form realm, and compared with the devas of the formless realm, it is deeper beyond comparison. The fainter the mind of fondness and delight, the higher the heaven one is reborn into at the end of life, the happier and more tranquil the life, and the less suffering one feels; the heavier the mind of fondness and delight, the heavier the suffering. If there is no mind of fondness and delight, one can depart from all dharmas, and the mind attains purity (viśuddha) and tranquility (praśama).