Jaiminīya (Talavakāra) Brāhmaṇa 2-8.315

Brilliance and spiritual luster indeed are the Jyotiragniṣṭoma. And procreation is from the middle of the body. In that the Jyotiragniṣṭoma is in the middle, he thus places light right in the middle of his body; one endowed with spiritual luster is born in his offspring. The Jyotiratirātra is at the end; this indeed is the known ford of the gods, namely the Jyotiratirātra, [thinking:] 'By the known ford of the gods, unharmed, may we unharmed reach the conclusion!' Now, for one of whom the Viśvajit and Abhijit are the two Agniṣṭomas on both sides and the six-day rite with light on both sides is in the middle, one who desires cattle should sacrifice with this. These four in the middle are Ukthyas; cattle indeed are ukthas; their stotriya-verses are a thousand. And these four Agniṣṭomas are on both sides; brahman indeed is the Jyotiragniṣṭoma; through brahman indeed he seizes cattle on both sides, to prevent their spilling away. The property of one who knows thus is not scattered away. It is possible, however, that he becomes just such as he is when he sacrifices. Therefore, whenever he thinks he has as it were reached the end of fortune, then he should sacrifice with this rite. Having sacrificed, he goes indeed to the heavenly world.

Now, these nine-day rites.

One who desires brilliance should sacrifice with this, namely the nine-day rite.