ब्राह्मणक्षत्रियविशां शूद्राणां च परंतप।कर्माणि प्रविभक्तानि स्वभावप्रभवैर्गुणैः॥
brāhmaṇa-kṣatriya-viśāṃ śūdrāṇāṃ ca parantapakarmāṇi pravibhaktāni svabhāva-prabhavair guṇaiḥ
Word by word
The verse says
The work of the priestly, the ruling, the producing and the serving groups is divided, Arjuna, according to the qualities that arise from what each person actually is.
In plain words
Here begins the passage in this book with the worst history, and it should be read slowly.
Four groups, four kinds of work. And the basis given for the division is svabhāva - a person's own nature.
Not birth. The word for birth does not appear. What the verse says and what it was later used to say are two different things, and both need stating.
Where you've felt this · in community
Your sister works in an office of thirty people. One of them is who everybody takes a dispute to. One will make the decision when nobody else will. One notices the money. One quietly keeps the place running. Nobody assigned any of this and none of it is in a job title. Within two years everyone knew which was which.
Going deeper
Nature, not birth, is what this verse names as the basis of the division, and the gap between that and what was built on it is the honest subject here.
Svabhāva means one's own becoming: the grain of a particular person. The claim is that people differ in temperament, that different work suits different temperaments, and that a society needs all four kinds. Stated that way it is unremarkable and probably true.
What happened afterwards is not in the verse and cannot be hidden behind it. The division hardened into birth, became hereditary, and was enforced for centuries with real cruelty. People were kept out of learning, out of temples, out of wells, and told the text required it. Anyone reading this page may be descended from people who paid for that, and no amount of careful reading about nature undoes it.
So the two things have to be held together. The text grounds this in temperament and the tradition grounded it in birth, and the second did enormous harm. Saying only the first is laundering. Saying only the second means never finding out what the verse actually claims.