Jaiminīya (Talavakāra) Brāhmaṇa 2-8.382

Moreover they say: Just twenty-four should be applied. The year has twenty-four half-months. Thus half-month by half-month they go establishing themselves in the year. Moreover they say: Just twelve should be applied. The year has twelve months. Thus month by month they go establishing themselves in the year. Moreover they say: Just six should be applied. There are six seasons. Thus in the seasons they go establishing themselves. Moreover they say: Just four should be applied. Four are the quarters, four-footed are cattle. Thus in the quarters and in cattle they go establishing themselves. Moreover they say: Just three should be applied. These worlds are three. Thus in these worlds they go establishing themselves. Moreover they say: Just two should be applied, namely the two pragāthas of the Śyaita and Naudhasa [sāmans]. Indeed, the two pragāthas of the Śyaita and Naudhasa are the most full of vital power. The sacrificer is two-footed, for a firm foundation.

Whoever goes along a road by turning back does not reach the end of it.

Now, he who goes along it without turning back, he alone reaches the end of it.

They go turning back, as it were, who apply [only] two.