The Difference Between the Buddha's Nirvana and the Arhat's Nirvana

The nirvana of the Buddha and the nirvana of an Arhat are fundamentally different. After the Buddha enters nirvana, he still manifests innumerable aggregates-bodies (five-skandha bodies) in the ten directions to liberate sentient beings. Therefore, the Buddha states that the aggregates-body is called the "liberated rūpa" (emancipated form). When the Buddha's karmic conditions for liberating beings in one world are exhausted, he extinguishes the physical body, which is expediently termed "nirvana." For example, when Śākyamuni Buddha attained nirvana in the Saha World, his physical body temporarily departed and was extinguished. Yet, Śākyamuni Buddha remains the Dharma Lord, the founder, and the teacher of the Saha World, and the beings of the Saha World still belong to the disciples taught by Śākyamuni Buddha. Simultaneously, Śākyamuni Buddha manifests immeasurable and boundless aggregates-bodies in the ten directions to teach and liberate beings throughout the universe. After an Arhat enters nirvana, there is no longer any aggregates-body or five skandhas. Thus, after an Arhat's nirvana, there is no "liberated rūpa"; their nirvana is not one of complete freedom, and their liberation is not ultimate.

The Buddha possesses the five aggregates yet is liberated. This "liberated rūpa" can be seen by the physical eyes of sentient beings and is not bound by any worldly dharmas. Although sentient beings also possess the five aggregates, they are bound by worldly dharmas and thus are not liberated. When the mind is liberated, the physical body is liberated; all five aggregates are liberated. Therefore, liberation does not necessarily require the extinction of the physical body and the five aggregates. Instead, it requires the elimination of improper mental thoughts and views. When mental thoughts transform into proper and true views and understanding, liberation is attained.