Now follows the Mahavrata ceremony. After having killed Vritra, Indra became great. When he became great, then there was the Mahavrata (the great work).
Next follows the Upanishad of the Samhita. The former half is the earth, the latter half the heaven, their union the air, thus says Mandukeya; their union is the ether, thus did Makshavya, teach it.