Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 5.9

Now, as to the fact that he sacrifices to Agni Kavyavāhana at the end:

the fathers have this [deity] for their Sviṣṭakṛt.

Therefore he sacrifices to him at the end.

Now, as to the fact that he touches water, the explanation for this has already been stated.

Now, as to the fact that after invoking and smelling the Iḍā, they do not eat of it:

the Iḍā is cattle.

[thinking], 'Lest I cut off the sacrificer's cattle.'

Now, as to why the adhvaryu gives to the fathers:

he thereby pleases the fathers.

Now, as to why they cleanse themselves with a strainer, the brāhmaṇa explanation of that has been stated.

Now, as to why they mutter a verse, they thereby perform a rite of auspiciousness.

Now, as to why, having gone towards the north, they revere the Gārhapatya and Āhavanīya [fires]:

having pleased [the fathers], they then state their wish among the gods at the end.

Moreover, the sacrifice to the fathers indeed concludes in the south.

They thereby make it conclude in the north.

Now, as to why, having stepped out towards the east, they revere the sun:

the sun is indeed the world of the gods;

the fathers are the world of the fathers.

They thereby step up to the world of the gods from the world of the fathers.

Now, as to why he does not utter the name of the sacrificer in the sūktavāka:

[it is thinking], 'Lest I cut off the sacrificer.'

Now, as to why they do not perform the patnīsamyājas:

[it is thinking], 'Lest we cut off the wives.'

Now, as to why, having gone towards the north, they perform [the rite] with the Tryambaka [cakes]:

they thereby please Rudra in his own quarter.

Moreover, the sacrifice to the fathers indeed concludes in the south.

They thereby make it conclude in the north.

Now, as to why, having sacrificed [thus], he sacrifices with an iṣṭi at the end:

the Sākamedha [offerings] indeed conclude with this.

Therefore, having sacrificed [thus], he sacrifices with an iṣṭi at the end.

Now, as to why he subsequently sacrifices with the full-moon sacrifice:

thus indeed his sacrifice with the Sākamedhas is performed in the first half of the month.