Śatapatha Brāhmaṇa ("of a hundred paths") 7.2.1.6

7.2.1.6

tathaivaitadyajamānaḥ | ātmānamukhāyāṃ yonau reto bhūtaṃ siñcati yonirvā ukhā tasmā etāṃ saṃvatsare pratiṣṭhāṃ saṃskarotīmameva lokamayaṃ vai loko gārhapatyastasminnenam prajanayati tasya yaḥ pāpmā yaḥ śleṣmā yadulbaṃ yajjarāyu tadasyaitābhirapahanti tadyadasyaitābhiḥ pāpmānaṃ nirṛtimapahanti tasmādetā nairṛtyaḥ

In like manner the Sacrificer now casts his own self, as seed, into the fire-pan, the womb; the fire-pan being indeed a womb. In the course of a year he prepares for that (self of his) this foundation, even this (terrestrial) world; the Gârhapatya being this world: therein he generates it. And whatever evil there is of it, whatever mucus, whatever inner and outer membrane, that he removes therefrom by these (bricks); and inasmuch as he thereby removes its evil, its corruption, these are Nirriti's (bricks).