Krishna offers a clear summary. The bright path and the dark path — these two are eternal features of the world. Through one, the soul attains moksha and never returns. Through the other, it circles back into the world of rebirth.
Picture a crossroads with two paths. One leads home — to a place from which there is no need to leave. The other leads to a marketplace — interesting and rewarding, but eventually one must return. The wise person knows which road to take.
These two paths have existed since the beginning of time. They are woven into the fabric of the cosmos. Yet Krishna is about to say something in the next shloka that puts all of this into a higher perspective.