BG Chap 18 - The natural activities of the kṣatriyas, vaiśyas and śūdras

The activities of a kṣatriya are: courage – he is not afraid during battle; power – cannot be surpassed by others; determination – even in times of great stress, his senses do not become fatigued; resourcefulness – expert in completing his tasks; he does not flee from battle even if his death is certain; generosity; and leadership – protects the citizens.

The duties of a vaiśya are agriculture – tills the land for producing corps; cow protection; and commerce – engaging in buying and selling. The activity of a śūdra is to serve the other three varṇas.