The timeline below shows where the term Shudra appears in The Bhagavad Gita. The colored dots and icons indicate which themes are associated with that appearance.
Discourse 9
...to “eternal peace.” No devotee of Krishna’s can be lost, and even women, vaishyas, and shudras can find this “highest path.” Brahmins and sages are nevertheless more devoted, and Arjuna’s devotion...
(full context)
Discourse 18
...courage, and generosity; vaishyas act from their natural inclination to “trade, cow-herding and ploughing;” and shudras’ nature is to serve. Contentment in one’s action according to these purposes can lead one...
(full context)