Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 2
श्रीचमस उवाचमुखबाहूरुपादेभ्य: पुरुषस्याश्रमै: सह ।चत्वारो जज्ञिरे वर्णा गुणैर्विप्रादय: पृथक् ॥ २ ॥
śrī-camasa uvācamukha-bāhūru-pādebhyaḥpuruṣasyāśramaiḥ sahacatvāro jajñire varṇāguṇair viprādayaḥ pṛthak
Śrī Camasa said: Each of the four social orders, headed by the brāhmaṇas, was born through different combinations of the modes of nature, from the face, arms, thighs and feet of the Supreme Lord in His universal form. Thus the four spiritual orders were also generated.
Those who are not spontaneously attracted to the devotional service of the Lord can be gradually purified by observing the varṇāśrama system of four social orders and four spiritual orders. According to Śrīdhara Svāmī, the brāhmaṇas are born of the mode of goodness, the kṣatriyas of a combination of goodness and passion, the vaiśyas of a combination of passion and ignorance and the śūdras of the mode of ignorance. Just as the four social orders are born from the face, arms, thighs and feet of the Lord’s universal form, similarly the brahmacārīs are generated from the heart of the Lord, the householder order from His loins, the vānaprasthas from His chest and the sannyāsa order from His head. A similar verse is found in the Ṛk-saṁhitā (8.4.19), as well as the Śukla-yajur Veda (34.11) and the Atharva Veda (19.66): “The brāhmaṇa appeared as His face, the king as His arms, the vaiśya as His thighs, and the śūdra was born from His feet.” It is understood that pure devotional service to the Lord has already been described by two of the Yogendras, Drumila and Āvirhotra. Camasa Muni now describes the system of varṇāśrama-dharma, because this system is meant to gradually purify those who are inimical to the Supreme Lord, bringing them back to their constitutional position of love of Godhead. Similarly, the virāṭ-rūpa, or universal form of the Lord, is an imaginary form meant to help the gross materialists gradually understand the position of the Personality of Godhead. Since the foolish materialist cannot understand anything beyond matter, he is encouraged to see the entire universe as a personal form of the Supreme Lord’s body. The impersonal conception of formlessness is a mere negation of temporary material variety without any concept of the Lord’s spiritual potency. The impersonal view is another kind of material speculative conception. The Supreme Lord is full of spiritual potencies under the principal headings hlādinī, or unlimited bliss, sandhinī, or eternal existence, and saṁvit, or omniscience. It is understood from this verse that the varṇāśrama-dharma system generated from the universal form of the Lord is a program offered by the Lord to engage the conditioned souls in a complete social and religious system that gradually brings them back home, back to Godhead.