This diagnostic 27 verses chapter details the three human proclivities - virtue, passion, and delusion, and it may be noted that v3, v4, and v19 that deal with the Nature and the Spirit are interpolated digressions. So as to pin down the interpolative v3 'n v4, one may read the opening verses of this chapter with Krishna's averment.
Ch14, V1
Pass I now thee that knowledge
With which sages free themselves.
paraṁ bhūyaḥ pravakṣhyāmi jñānānāṁ jñānam uttamam
yaj jñātvā munayaḥ sarve parāṁ siddhim ito gatāḥ
Ch14, V2
Knows whoso this reaches Me
Keeps thus births 'n deaths at bay.
idaṁ jñānam upāśhritya mama sādharmyam āgatāḥ
sarge 'pi nopajāyante pralaye na vyathanti cha,
Now these two interpolations,
V3
mama yonir mahad brahma tasmin garbhaṁ dadhāmy aham
sambhavaḥ sarva-bhūtānāṁ tato bhavati bhārata
The total material substance, prakṛiti, is the womb. I impregnate it with the individual souls, and thus all living beings are born.
V4
sarva-yoniṣhu kaunteya mūrtayaḥ sambhavanti yāḥ
tāsāṁ brahma mahad yonir ahaṁ bīja-pradaḥ pitā
O son of Kunti, for all species of life that are produced, the material nature is the womb, and I am the seed-giving Father.
It may be noted that the above two verses are about His role in the birth of beings that as seen, he had unerringly denied, and also, starting with the next (V5) till the very end (barring v19 that follows) this chapter is about human proclivities.
Ch14, V5
To tie the Spirit 'n body tight
Uses Nature as its threads
Virtue, passion as well delusion.
sattvaṁ rajas tama iti guṇāḥ prakṛiti-sambhavāḥ
nibadhnanti mahā-bāho dehe dehinam avyayam
Ch14, V6
Spirit as well gets well enticed
By the charms of life well-led
Steeped in wisdom and virtue.
tatra sattvaṁ nirmalatvāt prakāśhakam anāmayam
sukha-saṅgena badhnāti jñāna-saṅgena chānagha
Hence, it can be said that v3 'n v4 are not only digressive but also uncharacteristic interpolations. Likewise, in dealing with v19, we should focus on its preceding and the succeeding verses.
Ch14, V18
Echelons virtuous reach higher
Remain 'as is where' passionate
Go down ladder ever the deluded.
ūrdhvaṁ gachchhanti sattva-sthā madhye tiṣhṭhanti rājasāḥ
jaghanya-guṇa-vṛitti-sthā adho gachchhanti tāmasāḥ
V19
nānyaṁ guṇebhyaḥ kartāraṁ yadā draṣhṭānupaśhyati
guṇebhyaśh cha paraṁ vetti mad-bhāvaṁ so 'dhigachchhati
When wise persons see that in all works there are no agents of action other than the three guṇas, and they know me to be transcendental to these guṇas, they attain my divine nature,
thus breaking the narrative flow only to be succeeded by,
Ch14, V20
Out of orbit if thou go
Of Nature that grips thy mind
Freed be thou of recurring births.
guṇān etān atītya trīn dehī deha-samudbhavān
janma-mṛityu-jarā-duḥkhair vimukto 'mṛitam aśhnute
It can be seen that besides being intrusive, v19 is also a modified version of the penultimate verse of this chapter
Ch14, V26
It's by capping his nature
Wavers he not from the path
That which truly leads to Me
And in end he turns Brahman.
māṁ cha yo 'vyabhichāreṇa bhakti-yogena sevate
sa guṇān samatītyaitān brahma-bhūyāya kalpate
More so, it is only in these three interpolative verses that we see Krishna's personal involvement whereas in the rest of the text he presents himself as an impersonal being.