Link to purport by A C Bhaktivedanta Swami Srila Prabhupada

Transcript of Bhakti-Shastri class on this verse by Chaitanya Charan

Then what happens to one who lives in passion and in ignorance:

Bg 14.15

rajasi pralayaṁ gatvā
karma-saṅgiṣu jāyate
tathā pralīnas tamasi
mūḍha-yoniṣu jāyate

Synonyms: 

rajasi — in passion; pralayam — dissolution; gatvā — attaining; karma–saṅgiṣu — in the association of those engaged in fruitive activities; jāyate — takes birth; tathā — similarly; pralīnaḥ — being dissolved; tamasi — in ignorance; mūḍha–yoniṣu — in animal species; jāyate — takes birth.

Translation: 

When one dies in the mode of passion, he takes birth among those engaged in fruitive activities; and when one dies in the mode of ignorance, he takes birth in the animal kingdom.

rajasi pralayaṁ gatvā

If one dies in mode of passion then what happens?

karma-saṅgiṣu jāyate

Those who are attached to fruitive work, means those who are materialistic, if one dies in passion then one is reborn here in Karma-Sangisu, in attachment to fruitive action. 

tathā pralīnas tamasi

And if one dies in mode of ignorance then mūḍha-yoniṣu jāyate, 

So karma-saṅgiṣu refers to earthly planetary system here people are attached to fruitive work 

mūḍha-yoniṣu, we know mudha means either fool or donkey so those who live in animal like species or lower species or foolish species i.e. animals, that means if one lives in ignorance one attains lower species. 

So here what Krishna is telling that if we live in passion then we come back again.

End of transcription.