When the Shudra is unable to secure his living by service of the three other orders, then it is lawful for him to follow trade, tending of cattle, and the practice of the mechanical arts.
वाणिज्यं पाशुपाल्यं च तथा शिल्पोपजीवनम्। शूद्रस्यापि विधीयन्ते यदा वृत्तिर्न जायते॥