That little-witted Brahmana, who, moved by cupidity and folly, follows the practices assigned to Vaishyas, forgetful of his position as a Brahmana that is highly difficult to attain, comes to be considered as one who has become a Vaishya. Likewise, one who is a Vaishya by birth may, by following the practices of a Shudra, become a Shudra. Indeed, a Brahmana falling away from the duties of his own order. may go down to the status of even a Shudra.
वैश्यकर्म च यो विप्रो लोभमोहव्यपाश्रयः। ब्राह्मण्यं दुर्लभं प्राप्य करोत्यमल्पमतिः सदा॥ स द्विजो वैश्यतामेति वैश्यो वा शूद्रतामियात्। स्वधर्मात् प्रच्युतो विप्रस्ततः शूद्रत्वमाप्नुते॥