Aitareyabrahmana 4.21

4.21

āhūya dūrohaṇaṃ rohati, svargo vai loko dūrohanaṃ.
vāg āhāvo, brahma vai vāk.
sa yad āhvayate, tad brahmaṇāhāvena svargaṃ lokaṃ rohati
sa pacchaḥ prathamaṃ rohatīmaṃ tal lokam āpnoty,
athārdharcaśo 'ntarikṣaṃ tad āpnoty,
atha tripadyāmuṃ tal lokam āpnoty,
atha kevalyā tad etasmin pratitiṣṭhati ya eṣa tapati
tripadyā pratyavarohati yathā śākhāṃ dhārayamāṇas,
tad amuṣmim̐l loke pratitiṣṭhaty;
ardharcaśo 'ntarikṣe, paccho 'smim̐l loka.
āptvaiva tat svargaṃ lokaṃ yajamānā asmim̐l loke pratitiṣṭhanty
atha ya ekakāmāḥ syuḥ svargakāmāḥ, parāñcam eva teṣāṃ rohet.
te jayeyur haiva svargaṃ lokaṃ
na tv evāsmim̐l loke jyog iva vaseyur
mithunāni sūktāni śasyante traiṣṭubhāni ca jāgatāni ca.
mithunaṃ vai paśavaḥ paśavaś chandāṃsi, paśūnāṃ avaruddhyai

iv. 21 (xviii. 7). Having uttered the call, he mounts the difficult mounting; the difficult mounting is the world of heaven; the call is speech; speech is the holy power; in that he calls, thus with the call as the holy power he mounts the world of heaven. He mounts by Padas first; thus he obtains this world; then by half-verses; thus he obtains the atmosphere; then by three Padas; thus he obtains yonder world; then with the whole (verse); thus he who gives heat here finds support in this (world). By three Padas he descends as one holding a branch; thus he finds support in yonder world; by half-verses (he descends; thus he finds support) in the atmosphere; by Padas (he descends; thus he finds support) in this world. Thus, having obtained the world of heaven, the sacrificers find support in this world. For those who desire one only, (the world of) heaven, he should mount in the forward direction only; they will conquer the world of heaven, but they will not have long to live in the world. Pairing hymns are recited, Triṣṭubh and Jagatī; cattle are pairing; the metres are cattle; (verily they serve) to win cattle.