One verse

Srimad Bhagavatam 7.11.24

7.11.24

शूद्रस्य सन्नति: शौचं सेवा स्वामिन्यमायया । अमन्त्रयज्ञो ह्यस्तेयं सत्यं गोविप्ररक्षणम् ॥ २४ ॥

sudrasya sannatih saucam seva svaminy amayaya amantra-yajno hy asteyam satyam go-vipra-raksanam

sudrasya
of the sudra (the fourth grade of man in society, the worker)
sannatih
obedience to the higher classes (the brahmanas, ksatriyas and vaisyas)
saucam
cleanliness
seva
service
svamini
to the master who maintains him
amayaya
without duplicity
amantra-yajnah
performance of sacrifices simply by offering obeisances (without mantras)
hi
certainly
asteyam
practicing not to steal
satyam
truthfulness
go
cows
vipra
brahmanas
raksanam
protecting

Offering obeisances to the higher sections of society (the brahmanas, ksatriyas and vaisyas), being always very clean, being free from duplicity, serving one’s master, performing sacrifices without uttering mantras, not stealing, always speaking the truth and giving all protection to the cows and brahmanas—these are the symptoms of the sudra.