YV 3.6g

If he desire of a man, 'May I deprive him of brilliance, of the deities, of power', he should move the corner near the fire to one side or the other of the Ahavaniya; verily he deprives him of brilliance, of the deities, of power. If he desire of a man, 'May I unite him with brilliance, with the deities, with power' [4], he should set up for him the corner (of the post) near the fire in a line with the Ahavaniya; verily he unites him with brilliance, with the deities, with power. Thee that art winner of Brahmans, winner of nobles', he says that is according to the text. He winds round (the grass); the girdle is strength, the post is of the same height as the sacrificer; verily he unites the sacrificer with strength. He winds (it) round at the level of the navel; verily at the level of the navel he bestows upon him strength; therefore at the level of the navel men enjoy strength. If he desire of a man, 'May I deprive him of strength' [5], he should put (it) on either upwards or downwards; verily he deprives him of strength. If he desire, 'May Parjanya rain', he should put it on downwards, verily he brings down rain; if he desire, 'May Parjanya not rain', he should put it on upwards; verily he holds up rain. What is dug in belongs to the Pitrs, what is above the part dug in up to the girdle belongs to men, the girdle belongs to the plants [6], what is above the girdle up to the top to the All-gods, the top to Indra, the rest to the Sadhyas. The post is connected with all the gods; verily in setting up the post he delights all the gods. By means of the sacrifice the gods went to the world of heaven; they reflected, 'Men will equal us'; they blocked the way by the post and went to the world of heaven; the Rsis discerned that (world) by means of the post, and that is why it is called post [7]. In that be sets up the post, (it is) to discern the world of heaven.