Aitareyabrahmana 4.28

4.28

In the beginning the bṛhat and the rathaṃtara were here.
They were speech and mind: speech was the rathaṃtara, mind was the bṛhat.
The bṛhat, having been produced first, despised the rathaṃtara.
The rathaṃtara took an embryo; it produced the vairūpa.
Those two having come into being, the rathaṃtara and the vairūpa, despised the bṛhat.
The bṛhat took an embryo; it produced the vairāja.
Those two having come into being, the bṛhat and the vairāja, despised the rathaṃtara and the vairūpa.
The rathaṃtara took an embryo; it produced the śākvara.
Those three having come into being, the rathaṃtara, the vairūpa, and the śākvara, despised the bṛhat and the vairāja.
The bṛhat took an embryo; it produced the raivata.
Those were three on one side and three on the other, the six pṛṣṭha stotras.
At that time, those three metres could not reach the six pṛṣṭha stotras.
The gāyatrī took an embryo; it produced the anuṣṭubh.
The triṣṭubh took an embryo; it produced the paṅkti.
The jagatī took an embryo; it produced the atichandas.
Those were three on one side and three on the other, the six metres, the six pṛṣṭha stotras.
They were arranged in this manner; the sacrifice is arranged,
and it is arranged for that community where one, knowing this arrangement of the metres and the pṛṣṭha stotras, is consecrated, is consecrated.