rajasi pralayaḿ gatvā
karma-sańgiṣu jāyate
tathā pralīnas tamasi
mūḍha-yoniṣu jāyate

Translation of Bhagavad Gita 14.15

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.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

Some people have the impression that when the soul reaches the platform of human life it never goes down again. This is incorrect. According to this verse, if one develops the mode of ignorance, after his death he is degraded to an animal form of life. From there one has to again elevate himself, by an evolutionary process, to come again to the human form of life. Therefore, those who are actually serious about human life should take to the mode of goodness and in good association transcend the modes and become situated in Krishna consciousness. This is the aim of human life. Otherwise, there is no guarantee that the human being will again attain to the human status.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

Those who die in the mode of rajas are born among men attached to work (karma sangisu).

Commentary by Sri Ramanuja of Sri Sampradaya:

14.15 (a) Meeting with death when Rajas is preponderant, one is reborn in the families of those who act for the sake of fruits for themselves. Being reborn in such families, he becomes qualified to perform auspicious acts which constitute the way for attaining heaven and the like. (b) Similarly, one who dies when Tamas is preponderant is born in the wombs of beings lacking in intelligence, namely, in the wombs of dogs, pigs etc. The meaning is that he is reborn as one incapable of realising any human end.

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

Continuing Lord Krishna explains the result of raja guna or mode of passion being prredominant at the time of death is that the jiva or embodied being is born into families that are are involved in vigorous activity, Likewise the result of tama guna or mode of ignorance being predominant at the moment of death then the jiva is born in the wombs of irrational species as animals.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Sri Madhvacharya did not comment on this sloka.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

Lord Krishna states that if death comes upon a jiva or embodied being while predisposed to raja guna or the mode of passion then one takes birth next from those who are obsessed to perform actions in anticipation of rewards . Also a jiva dying while under the influence of tama guna or mode of ignorance is forced to take birth as an animal in the next life.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

14.15 Pralayam gatva, when one does; rajasi, while the quality of rajas predominates; jayate, he is born; karma-sangisu, among people attached to activity, among human beings having attachment to work. Tatha, similarly, in that very way; pralinah, when one dies; tamasi, while tamas predominates; jayate, he takes birth; mudha-yonisu, among the stupid species, such as animals etc. A summary of the idea of the preceding (three) verses is being stated:

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

14.14-15 Yada etc. Rajasi etc. When the Sattva is predominantly on the increase on account of increase on account on account of incessantly practising actions of the Sattva throughout the entire life-at that [time] having met dissolution [of body], one attains the auspicious worlds. Likewise whosoever has practised throughout his life the activities of the Rajas, he, by his [last] journey attains manhood for mixed enjoyment. Likewise : i.e. in the same order, if one practises action of the Tamas alone by one’s entire life, then [on his death] he is reborn in the bodies of the hell, of the animals, of the trees and so on. Those, who explain [the passage under study to the effect] : ‘These results [are for him in whom] the Sattva etc., have predominantly increased only at the time of death’ – these commentators have not correctly entered into (grasped) the behaviour of the embodied. For, nothing but delusion arises, by all means at the last moment, without exception in the case of one and all. However, with regard to our explanation [given above] these passages and other verses (Ch. VIII, 5ff) speak in one voice.

Sanskrit Shloka Without Transliteration Marks:

rajasi pralayam gatva
karma-sangisu jayate
tatha pralinas tamasi
mudha-yonisu jayate

Sanskrit to English Word for Word Meanings:

rajasi — in passion; pralayam — dissolution; gatvā — attaining; karma-sańgiṣu — 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.