Srimad Bhagavatam — Ekadasha Skandha, Shloka 52
Sāṅkhya Enumeration of Tattvas, Distinction of Puruṣa–Prakṛti, and the Mechanics of Birth and Death
सत्त्वसङ्गादृषीन्देवान् रजसासुरमानुषान् । तमसा भूततिर्यक्त्वं भ्रामितो याति कर्मभि: ॥ ५२ ॥
sattva-saṅgād ṛṣīn devān rajasāsura-mānuṣān tamasā bhūta-tiryaktvaṁ bhrāmito yāti karmabhiḥ
受业力驱使而漂泊的系缚灵魂，依善性（sattva）之接触而生于圣贤或天众之中；依激情（rajas）而为阿修罗或人；依愚昧（tamas）而生为鬼类或畜生界。
The word tiryaktvam means “the status of an animal,” which includes all lower forms of life, such as beasts, birds, insects, fish and plants.
FAQs
This verse explains that association with sattva elevates one to the level of sages and devas, rajas leads to human/asuric conditions, and tamas degrades one to animal or ghostly states—one wanders accordingly due to karma.
In the Uddhava Gita, Krishna is teaching Uddhava how material nature (the gunas) binds the soul and how karmic action, shaped by those modes, propels the jiva through higher and lower births.
Choose sāttvika association and habits (truthfulness, cleanliness, self-control, uplifting company), reduce rājasic agitation (restless desire and ego-driven work), avoid tāmasic choices (intoxication, laziness, cruelty), and orient actions toward devotion to transcend the gunas.