Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 15

Sanskrit:

वर्णानामाश्रमाणां च जन्मभूम्यनुसारिणी: ।आसन् प्रकृतयो नृणां नीचैर्नीचोत्तमोत्तमा: ॥ १५ ॥

ITRANS:

varṇānām āśramāṇāṁ cajanma-bhūmy-anusāriṇīḥāsan prakṛtayo nṝnāṁnīcair nīcottamottamāḥ

Translation:

The various occupational and social divisions of human society appeared according to inferior and superior natures manifest in the situation of the individual’s birth.

Purport:

According to Śrīla Viśvanātha Cakravartī Ṭhākura, the brāhmaṇas and sannyāsīs, being situated on the head of the universal form of the Lord, are considered to be the most qualified, whereas the śūdras and gṛhasthas, being on the legs or loins of the Personality of Godhead, are considered to be in the lowest position. A living entity is born with a certain amount of intelligence, beauty and social opportunity, and he is therefore situated in a particular occupational and social position within the varṇāśrama system. Ultimately, such positions are external designations, but since the majority of human beings are conditioned by the external energy of the Lord, they should act according to the scientific varṇāśrama divisions until they reach the stage of jīvan-mukta, or liberated life.