And the greatest piety of the Vaiśyas and Śūdras at that time consisted of serving the Brāhmaṇas and Ksatriyas and specially for the Śūdras the highest religion was to serve people of all Varnas.
स्वधर्मः परमस्तेषां वैश्यशूद्रं तदागमत्। पूजां च सर्ववर्णानां शूद्राश्चनुर्विशेषतः॥