Bhagavad Gita · 8.26

शुक्लकृष्णे गती ह्येते जगतः शाश्वते मते।एकया यात्यनावृत्तिमन्ययावर्तते पुनः॥

śhukla-kṛṣhṇe gatī hy ete jagataḥ śhāśhvate mate ekayā yāty anāvṛttim anyayāvartate punaḥ

The bright and dark paths of the world are considered eternal. By one, a person attains the state of no return; by the other, one returns again.

— Bhagavad Gita 8.26

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