Chapter 8 · The Imperishable Absolute · Krishna said
Bhagavad Gita 8.25 — The path of smoke
धूमो रात्रिस्तथा कृष्णः षण्मासा दक्षिणायनम्। तत्र चान्द्रमसं ज्योतिर्योगी प्राप्य निवर्तते ॥
dhūmo rātristathā kṛṣṇaḥ ṣaṇmāsā dakṣiṇāyanam | tatra cāndramasaṃ jyotiryogī prāpya nivartate ||
Meaning
Smoke, night, the dark fortnight, the six months of the sun's southern course — the yogi departing by this path reaches the light of the moon and returns.