Saṃyuktāgama, Volume One  1

The World-Honored One addressed the bhikṣus: You should contemplate the impermanence of the form aggregate. One who is able to truly perceive the impermanence of the form aggregate is practicing right contemplation. If one can correctly contemplate the impermanence of the form aggregate, one will develop revulsion toward the form aggregate. Developing revulsion toward the form aggregate leads to the cessation of desire and attachment to it. One who has completely ceased desire and attachment toward the form aggregate is one whose mind is liberated.

Similarly, contemplate the impermanence of the feeling aggregate, perception aggregate, volitional formations aggregate, and consciousness aggregate. One who is able to truly perceive the impermanence of these four aggregates—feeling, perception, volitional formations, and consciousness—is practicing right contemplation. One who practices right contemplation will develop revulsion toward these four aggregates. Developing revulsion leads to the complete cessation of desire and attachment toward them. One who has completely ceased desire and attachment toward these four aggregates is one whose mind is liberated.

Thus, O bhikṣus, one whose mind is liberated, if wishing to personally attest to having attained liberation and to enter Nirvāṇa without residue, is able to personally attest to it without requiring another's attestation. He will declare: My endless cycle of birth and death has come to an end in this life; there will be no further rebirth. My holy life is established; my mind is purified and free from defilements. The task of liberation has been accomplished in this life. I myself know that I will not experience existence in the realm of desire, the realm of form, or the formless realm; I will not be reborn in the Triple Realm. At the end of this life, I will enter Nirvāṇa without residue.

The World-Honored One further addressed the bhikṣus: You should contemplate the five aggregates as suffering, empty, and non-self. Such contemplation is right contemplation. One who is able to practice right contemplation will develop revulsion toward the five aggregates. Developing revulsion toward the five aggregates leads to the cessation of desire and attachment to them. One who has completely ceased desire and attachment toward the five aggregates, I declare, is one whose mind is liberated. One whose mind is liberated, if wishing to personally attest to having attained liberation, is able to attest to it himself. He attests: Birth is ended, the holy life is fulfilled, what had to be done is done, and there is no further existence to be experienced. Then the bhikṣus, having heard the Buddha's teaching, rejoiced and earnestly practiced accordingly!