Verse 19

छायातपप्रसरयोः प्रकाशतमसोर्यथा ।न संभवति संबन्धस्तथा वै देहदेहिनोः

In plain words

Just as no connection is possible between the spread of shade and the spread of sunlight, between light and darkness, so indeed it is between the body and the embodied.