धूमो रात्रिस्तथा कृष्णः षण्मासा दक्षिणायनम्।तत्र चान्द्रमसं ज्योतिर्योगी प्राप्य निवर्तते॥
dhūmo rātris tathā kṛṣṇaḥ ṣaṇ-māsā dakṣiṇāyanamtatra cāndramasaṃ jyotir yogī prāpya nivartate
Word by word
The verse says
Smoke, night, the dark half of the month, the six months of the sun's southern course — departing then, the practitioner reaches the light of the moon and returns.
In plain words
The other route, made of things that obscure: smoke, night, the waning moon.
And notice what happens at the end of it. Not punishment. Not loss.
A real attainment, and then a return. The good outcome here is simply one that does not hold.
Where you've felt this · in health
Every year before the wedding season your uncle loses twelve kilos, and by the following monsoon he has put them back. He is not exaggerating about the twelve kilos — he genuinely loses them, every year. Nothing about the way he does it was ever built to be kept.
Going deeper
A real gain that does not last is a category most people have not thought about carefully, and it is the whole subject here.
The moon in this passage is not a failure. It is light, and it is genuinely reached. But it is borrowed light, and the route that leads there is described as a circuit rather than a road — you arrive, you are there, and then you are back where you started with the memory of having been somewhere.
This is the same objection the chapter made to heaven a few verses earlier, restated in the language of the older cosmology.
The question it raises is one you can actually use. Look at whatever you are working toward at the moment and ask whether it is built to be kept, or whether it is the kind of gain that comes with a return journey already included.