Krishna describes the shukla gati — the path of light. Fire, radiance, daytime, the bright fortnight, the six months of Uttarayana — these mark the luminous path. Those who know Brahman and depart during this time reach Brahman.
The Upanishads call this the devayana marga — the path of the gods. Just as sunrise illuminates everything, this path of light carries the soul toward knowledge and liberation.
Tradition recalls that Bhishma Pitamaha himself waited for the arrival of Uttarayana before relinquishing his body — a choice rooted in this very teaching.