Srimad Bhagavatam Canto 11, Chapter 21, Text 06

SB 11.21.6

vedena nama-rupani
 visamani samesv api
dhatusuddhava kalpyanta
 etesam svartha-siddhaye
My dear Uddhava, although all material bodies are composed of the same five elements and are thus equal, the Vedic literatures conceive of different names and forms in relation to such bodies so that the living entities may achieve their goal of life.
The words nama-rupani visamani refer to the system of varnasrama-dharma, in which members of human society are designated according to four social and four occupational divisions. Those dedicated to intellectual or religious perfection are called brahmanas, those dedicated to political perfection are called ksatriyas, those dedicated to financial perfection are called vaisyas, and those dedicated to eating, sleeping, sex and honest work are called sudras. Such propensities arise from the three modes of material nature (goodness, passion and ignorance), because the pure soul is not materially intellectual, ambitious for power, enterprising or servile. Rather, the pure soul is always absorbed in loving devotion to the Supreme Lord. If the various propensities of a conditioned soul are not engaged in the varnasrama system, they will certainly be misused, and thus that person will fall down from the standard of human life. The Vedic system is designed by the Lord so that conditioned souls may pursue their individual achievements and at the same time advance toward the ultimate goal of life, Krsna consciousness. Just as a doctor deals with a crazy man by speaking to him sympathetically in terms of his false conception of life, one who understands the Vedic literature engages the living entities according to their illusory identification with the elements of matter. Although all material bodies are composed of the same material elements and are thus qualitatively identical, as described here by the word samesu, the Vedic social system, varnasrama, is created to engage all human beings in Krsna consciousness according to their various degrees of material identification. The absolute good is the Supreme Lord Himself, and that which approaches the Supreme Lord becomes similarly good. Because the sun is the source of heat within this world, an object that approaches the sun becomes hotter and hotter until it merges into fire. In the same manner, as we approach the transcendental nature of the Personality of Godhead, we automatically become surcharged with absolute goodness. Although this knowledge is the real basis of the Vedic literature, mundane piety is enjoined and sin is prohibited so that one can gradually come to the platform of material goodness, whereupon spiritual knowledge becomes visible.
Srimad Bhagavatam Canto 11, Chapter 21, Text 05
Srimad Bhagavatam Canto 11, Chapter 21, Text 07