May glory come to both of us (teacher and pupil) together! May Vedic light belong to both of us! Now let us explain the Upanishad (the secret meaning) of the union (samhita), under five heads, with regard to the worlds, the heavenly lights, knowledge, offspring, and self (body). People call these the great Samhitas. First, with regard to the worlds. The earth is the former element, heaven the latter, ether their union;

In plain words: Teacher and student pray that they both gain honor and the light of sacred knowledge. The teacher then begins explaining hidden meanings of 'joining' in five areas, starting with the worlds: earth and heaven are joined by the space between them.