B.G 18.40 and 41

na tadasti pṛthivyāṃ vā divi deveṣu vā punaḥ। sattvaṃ prakṛtijairmuktaṃ yadebhiḥ syāttribhirguṇaiḥ ॥40॥

There is no being on earth or in heaven among the gods that is free from the three qualities born of nature (Prakrti).

brāhmaṇakṣatriyaviśāṃ śūdrāṇāṃ ca parantapa। karmāṇi pravibhaktāni svabhāvaprabhavairguṇaiḥ ॥41॥

O Arjuna, the duties of the Brahmins (class of intellectuals and wise ones), Kshatriyas (warrior class), Vaishyas (business class), and Shudras (service class) are divided according to the qualities inherent in their own nature (svabhāva).

Gīta Tātparya 18.40 and 41

The word 'sattvam' in the context means living beings. As liberated beings transcend qualities, the phrase "on earth, in heaven, or among gods" is specially used to address all non-liberated beings, including gods.
The classification is based on which quality is dominant among the sattvic, rajasic and tamasic qualities. Warriors are characterized by a predominance of sattva with some rajas, while merchants and laborers are characterized by a predominance of tamas with very little sattva.
Those who are purely sattvic, those who are slightly mixed with rajas, those equally mixed with rajas, and those who are slightly mixed with tamas - all within the rajasic-sattvic category are worthy of liberation because - "From sattva, knowledge arises". Even a barbarian, if he is predominantly in goodness, is always considered a devotee of the Lord.
By remembering Lord Viṣṇu while performing actions, the actions become pure and one is not bound.

sattvaṁ jīvajātaṁ। muktānāṁ guṇātītatvāt "pṛthivyāṁ divi deveṣu vā" iti viśeṣaḥ।

The word 'sattvam' in the context means living beings. As liberated beings transcend qualities, the phrase "on earth, in heaven, or among gods" is specially used.

"yathetṣṭaṃ sañcaranto'pi muktā bhūmyādiga na tu। grāmasthā api na grāmyā vailakṣaṇyāddhi sajjanāḥ। narādhamāḥ tāmaseṣu sāttvikāḥ tatra rājasāḥ। daityabhṛtyā mahādaityā mukhyatāmasatāmasāḥ॥ rājasāstu narāḥ tatra viprā rājasasāttvikāḥ।

"Even though they move about as they wish, the liberated ones who go to earth and other places are not ordinary mortals, having different qualities than mortals, and are good people. Those lowest humans are mixed with qualities of goodness and darkness. Servants of demons are mixed with qualities of Rajas and darkness, and great demons are predominantly in deep ignorance. Humans are predominantly passionate, while those virtuous wise ones are mixed with passion and goodness.

tatrasthaśuddhasattvāstu parahaṃsāḥ prakīrtitāḥ। haṃso bahūdaḥ kuṭajo vanastho naiṣṭhiko gṛhī॥

Those situated purely in the mode of goodness are proclaimed as great-swans, the highest among ascetics. Many-giving-Swans (haṃso-bahūdaḥ), born-in-the-forest (kuṭajaḥ), dwelling-in-the-forest (vanasthaḥ), steadfast-ones (naiṣṭhikaḥ), and householders (gṛhī) - respectively these are dominated by the quality of rajas as they progressively engage more in external actions. Whereas the duties of the paramahamsas are purely spiritual, starting with tranquillity.

devādeḥ karmabāhulyaṃ na liṅgaṃ rajasaḥ kvacit॥ na hi viṣṇoḥ calet teṣāṃ manaḥ karmakṛtāvapi। anyeṣāṃ calacittatvāt prāyaḥ syāt karma rājasam॥ yadi tat smārakaṃ viṣṇoḥ vidyāt sāttvikameva tu॥

The multitude of actions performed by the gods and others is not necessarily an indication of the presence of rajas. Indeed, their minds remain steady on Viṣṇu even while performing actions, unlike others whose minds are unsteady, leading to passionate actions. Thus, if one remembers Viṣṇu, even their actions are pure.

dharmārthahiṁsanāgniśca viśeṣo brahmacāriṇaḥ। paitṛkaṃ cāpi yatito dārāstu gṛhiṇastataḥ॥ asaṅgo grāmyasantyāgaḥ paśvahiṁsā gṛhasthataḥ। vanasthasya viśeṣo'yaṁ sarveṣāmitarat samam॥"

For a celibate, duty, wellbeing, non-violence, and fire are significant compared to an ascetic. The ancestral rites and the wife are important for a householder. The forest dweller's speciality is detachment and renunciation of worldly life, along with non-violence towards animals, which differentiates them from householders. All other duties are equally applicable to all."

iti ca।

- stated thus as well.

"sāttvikāḥ svalparajasaḥ kṣatriyāḥ sattvarājasāḥ। vaiśyāḥ śūdrā atisvalpasattvādhikyena tāmasāḥ॥

"Warriors are characterized by a predominance of sattva with some rajas, while merchants and laborers are characterized by a predominance of tamas with very little sattva.

ye tu bhāgavatā varṇāsteṣāṁ bhedo'yamīritaḥ। sattvādhikaḥ pulkaso'pi yastu bhāgavataḥ sadā॥

The distinction among the classes of devotees of the Lord is declared here. Even a barbarian, if he is predominantly in goodness, is always considered a devotee of the Lord.

traividyamātrā viṣṇorye sarvādhikye sasaṃśayāḥ। anyādhikyaṃ na manyante śrīśād rājasarājasāḥ। ajñā viṣṇau dveṣahīnāḥ sarve rājasatāmasāḥ।

Those who are knowledgeable only in the three Vedas and have doubts about Vishnu's supremacy and do not consider any other supremacy beyond the lord of prosperity, they are classified as passionate-passionate. Those who are ignorant of Vishnu, are free from hatred towards the Lord, and are classified as passionate-ignorant.

pitṛgandharvapūrvāśca munayo devatā iti॥ sāttvikāḥ trividhāstatra śreṣṭhā evottarottarāḥ। devā indro viriñcādyā iti tredhaiva devatāḥ। kramottarāḥ śivo vāṇī brahmā caivottarottarāḥ॥

The beings in the mode of goodness are categorized into three types, each progressively superior. The principal deities Shiva, Vani, and Brahma are most superior. The gods, starting with Indra and Virinchi are next. The ancestors, celestial musicians and sages come subsequently in a successive order.

sattvasattvamahāsattvasūkṣmasattvaḥ caturmukhaḥ। yasmādvimuktiḥ syānmuktāvevaṃ sukha-kramaḥ॥"

The four-faced lord Brahma is possessed with Sattwa-Sattwa, Maha-Sattwa, and Subtle-Sattwa qualities. Even among the liberated, thus follows the order of happiness."

iti ca।

- stated thus, as well.

viṣṇau kiñcit aprītiyuktāḥ tāmasamadhye sāttvikā narādhamā ityarthaḥ। rājasānāṃ madhye sāttvikā eva bhāgavataviprādayaḥ।

Among the Tamsic ones, those lower humans with limited displeasure with Lord Vishnu tend to have a sattvic tinge. Among the Rajasic, those with sattvic dominance are devotees of the Lord and wise ones.

rajasasthasāttvikeṣveva śuddhasāttvikāḥ kiñcidrajoyuktasāttvikāḥ samarajoyuktasāttvikāḥ sattvāt kiñcidūnatamoyuktasāttvikā iti varṇabhedaḥ।

The classification of types includes those who are purely sattvic, those who are slightly mixed with rajas, those equally mixed with rajas, and those who are slightly mixed with tamas, all within the rajasic-sattvic category.

sattvapradhānatvāt etānārabhya uttarottaraṃ sarvepi mokṣayogyāḥ।

Because of the predominance of goodness starting from these, all subsequent ones are also worthy of liberation.

"sattvāt sañjāyate jñānam" ityādeḥ।

"From sattva, knowledge arises," and so forth are stated thus.

"sattvādhiko mokṣayogyo yogyo'ndhatamasastathā। tama uttaro rajobhūyān samo vā sṛtipātrakaḥ॥"

"One who is predominated by sattva is eligible for liberation; similarly, one who is dominated by tamas is eligible for deep darkness. Superior to him is the one predominated by rajas, fit for worldly existence."

iti ca॥

- stated thus, as well.