The Trikayasutra, the Three Body Sutra:
As the title suggests, this sūtra describes the three bodies of the Buddha. While the Buddha is dwelling on Vulture Peak in Rājgṛha, the Bodhisattva Kṣitigarbha asks whether the Tathāgata has a body, to which the Buddha replies that the Tathāgata has three bodies: a dharmakāya, a saṃbhogakāya, and a nirmāṇakāya. The Buddha goes on to describe what constitutes these three bodies and their associated meaning.
The Anityatāsūtra, The Sūtra on Impermanence:
In this brief sūtra, the Buddha reminds his followers of one of the principal characteristics of saṃsāric existence: the reality of impermanence. The four things cherished most in this world, the Buddha says—namely good health, youth, prosperity, and life—are all impermanent