This chapter of 28 slokas, known as akshara parabrahma yoga - The Indestructible Brahman - emphasizes the need of un-wavered devotion to the Supreme so as to attain Him. It also describes the science of meditation to reach the Supreme by understanding the nature of the Brahman. And s 22 is a seemingly concluding statement of the Lord that only through un-swerved devotion the Supreme could be reached from which there is no return (s 21).
Then appear s23 to s28 which if literally taken would imply that if one dies when the moon is on the ascent he would go to heaven and, to hell if it's other way round. Needless to say, these slokas spelling superstition in an otherwise thought-elevating treatise are but interpolations.
It is worth noting that Sir Edwin Arnold dismissed these as the work of some vedãnti and thought it fit, justifiably at that, not to include them in his 'Song Celestial'. In this connection it may be noted that the relationship between the state in which a person dies and his imminent rebirth is covered in s 14 and s15 of c14, which seem to be authentic.
It can be seen that s5, places the cart before the horse. Besides, s9-s14 too, are interpolations going by their content that's out of context. It is worth noting that s1-s4, s6-s8 and s15-s22, if read together would bear an unmistakable continuity of argument that the interpolations deprive.
1
Thus spoke Arjuna:
O Lord appraise what's Brahman
Lies what within 'n backs action
Nature of deities besides the beings.
2
What is that guides bodily acts,
What makes yogis realize Thee?
3
Thus spoke the Lord:
Self-Imperishable is Brahman
But dwells it yet there in beings
Brings that forth is Act Supreme.
4
Perish as beings all in time
Spirit that lasts of them is Me.
6
In the end the way one tends
Charts that future course he takes.
7
If thou act with this in mind
In the end thou gain Me true,
By My word now opt for war
With thy strength 'n skill I gave.
8
Me they reach whoso keep
On Me focus as they work.
15
Having come to stay with Me
Get they rid of births and deaths.
16
Journey to Brahman holds return ticket
Journeys back none abode from Mine.
17
Wise all realize days Brahman
Ages thousands make with nights.
18
By day as He brings beings
Un-manifests He all by night.
19
It's all rebirths through His day
But with nightfall cease they all
As He wakes up puts He back.
20
My State Supreme that never ends
Un-manifested it's above Brahman.
21
It's My Abode that Supreme
For man to reach not to leave.
22
It's through devotion that thee gain
State Supreme that pervades worlds.
Ends thus:
Cycle of Creation,
The Eighth Chapter
Of Bhagavad-Gita,
Treatise of self-help.