Bhagavad Gita · Chapter 4: Knowledge and the Renouncing of Action

Bhagavad Gita 4.13

cāturvarṇyaṃ mayā sṛṣṭaṃ guṇakarmavibhāgaśaḥ | tasya kartāramapi māṃ viddhyakartāramavyayam ||

The four social orders were created by me according to the division of qualities and actions. Though I am their maker, know me to be the changeless one who does not act.

Modern context

The verse says that the four orders of society were arranged according to guna and karma, that is, a person's qualities and the work that follows from them. Those two are the only basis it gives, and birth is not mentioned. Read in this way it describes something visible in every society: people differ in temperament, and thinkers, protectors, traders and makers are all needed. The second half makes the larger point. Krishna is the source of this order and is still not bound as its doer, which is the freedom in action that the chapter goes on to teach.