Aitareyabrahmana 2.35

2.35

pra vo devāyāgnaya ity anuṣṭubhaḥ
prathame pade viharati, tasmāt stry ūrū viharati
samasyaty uttare pade, tasmāt pumān ūrū samasyati.
tan mithunam, mithunam eva tad ukthamukhe karoti prajātyai
prajāyate prajayā paśubhir ya evaṃ veda
pra vo devāyāgnaya ity evānuṣṭubhaḥ.
prathame pade viharati, vajram eva tat parovarīyāṃsaṃ karoti.
samasyaty evottare pade.
ārambhaṇato vai vajrasyāṇimātho daṇḍasyātho paraśor.
vajram eva tat praharati dviṣate bhrātṛvyāya vadhaṃ,
yo 'sya stṛtyas tasmai startavai

ii. 35 (x. 3). ‘Forward to your god Agni’ are Anuṣṭubh (verses ). He separates the two first Padas; therefore a woman separates her thighs. He creates the last two Padas; therefore a man unites his thighs. That is a pairing; verily thus he makes a pairing at the beginning of the litany, for generation; he is propagated with offspring, with cattle, who knows thus.

‘Forward to your god Agni’ are Anuṣṭubh (verses). He separates the first two Padas, verily thus he makes a thunderbolt broader below; he unites the last two Padas; at the beginning a thunderbolt is narrow, and so of a club and of an axe; verily thus he hurls a thunderbolt at the foe who hates him, as a weapon to lay low whom he has to lay low.