Near the end of the sixth chapter Arjuna asks the question nobody in a devotional text is supposed to ask. What happens to the person who has faith but cannot hold to the practice, whose mind wanders away, who fails to reach perfection? Do they perish like a torn cloud, having lost both the ordinary rewards of the world and the goal they were reaching for, with nothing to stand on?
The answer is the Gita's only sustained treatment of spiritual failure, and it is unusually generous. No one who does good comes to a bad end, Krishna says, either here or hereafter. Such a person attains the worlds of those who have acted well, dwells there for a long time, and is then born in the house of the pure and prosperous, or, rarer than that, into a family of practitioners of yoga, which is a birth harder to obtain in this world.
The crucial clause follows. In that birth the person regains the mental disposition of the earlier body, and from there strives again toward perfection. The effort is not lost and does not have to be repeated from the beginning. Even wishing to know about this discipline, the chapter adds, carries someone past the merely ritual observance of the scriptures.
That is a doctrine of accumulated progress across lifetimes, and it changes the emotional temperature of the whole practice. The chapter has just finished describing a discipline that almost nobody completes. Rather than treating incompletion as damnation, it treats it as an interrupted apprenticeship, which is one reason this passage is quoted so often to beginners.