द्वावेव वर्जयेन्नित्यमनध्यायौ प्रयत्नतः । स्वाध्यायभूमिं चाशुद्धमात्मानं चाशुचिं द्विजः ॥ १२७ ॥
sanskrit
Let a twice-born man always carefully interrupt the Veda-study on two (occasions, viz.) when the place where he recites is impure, and when he himself is unpurified.
english translation