Bhagavad Gita · 14.27

ब्रह्मणो हि प्रतिष्ठाहममृतस्याव्ययस्य च।शाश्वतस्य च धर्मस्य सुखस्यैकान्तिकस्य च॥

brahmaṇo hi pratiṣhṭhāham amṛtasyāvyayasya cha śhāśhvatasya cha dharmasya sukhasyaikāntikasya cha

For I am the foundation of Brahman — the immortal, the imperishable, the eternal dharma, and the absolute bliss.

— Bhagavad Gita 14.27

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)