One verse

Bhagavad Gita 18.44

18.44

कृषिगौरक्ष्यवाणिज्यं वैश्यकर्म स्वभावजम् | परिचर्यात्मकं कर्म शूद्रस्यापि स्वभावजम् ||१८-४४||

kṛṣigaurakṣyavāṇijyaṃ vaiśyakarma svabhāvajam . paricaryātmakaṃ karma śūdrasyāpi svabhāvajam ||18-44||

kṛṣi
plowing
go
of cows
rakṣya
protection
vāṇijyam
trade
vaiśya
of a vaiśya
karma
duty
svabhāva-jam
born of his own nature
paricaryā
service
ātmakam
consisting of
karma
duty
śūdrasya
of the śūdra
api
also
svabhāva-jam
born of his own nature

Farming, cow protection and business are the natural work for the vaiśyas, and for the śūdras there are labor and service to others.