YV 3.6b

The altars are the breaths; if the Adhvaryu were to go past the altars to the west, he would mingle the breaths, he would be liable to die. The Hotr is the navel of the sacrifice; the expiration is above the navel, the inspiration is below; if the Adhvaryu were to go past the Hotr to the west, he would place the expiration in the inspiration, he would be liable to die. The Adhvaryu should not accompany the song; the Adhvaryu's strength is his voice; if the Adhvaryu were to accompany the song, he would confer his voice on the Udgatr [5], and his voice would fail. The theologians say, 'The Adhvaryu should not go beyond the Sadas to the west before the Soma offering is completed. Then how is he to go to offer the sacrifices in the southern fire? Because that is the end of the fires. But how are the gods to know whether it is the end or not?' He goes round the Agnidh's altar to the north and offers the sacrifices in the southern fire; verily he does not mingle the breaths. Some of the altars are besprinkled, some not; those which he besprinkles he delights; those which he does not besprinkle he delights by indicating them. The Vaisarjana offerings are made for the world of heaven. He offers in the Garhapatya with two verses; the sacrificer has two feet; (verily it serves) for support. He offers in the Agnidh's fire; verily he approaches the atmosphere; he offers in the Ahavaniya; verily he makes him go to the world of heaven. The Raksases sought to harm the gods as they were going to the world of heaven; they smote away the Raksases through Soma, the king, and making themselves active went to the world of heaven, to prevent the Raksases seizing them. The Soma is ready at hand; so he offers [1] the Vaisarjanas, to smite away the Raksases.