Bhagavad Gita · 8.24

अग्निर्ज्योतिरहः शुक्लः षण्मासा उत्तरायणम्।तत्र प्रयाता गच्छन्ति ब्रह्म ब्रह्मविदो जनाः॥

agnir jyotir ahaḥ śhuklaḥ ṣhaṇ-māsā uttarāyaṇam tatra prayātā gachchhanti brahma brahma-vido janāḥ

Those who know Brahman depart during the influence of fire, light, daytime, the bright fortnight, and the six months of the northern course of the sun — they attain Brahman.

— Bhagavad Gita 8.24

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