Varahashrautasutra 3.2.2.36

3.2.2.36

vācam̐ visṛjyāgnīdhrīyamupatiṣṭhante-yuvaṃ tamindrāparvatā puroyudhā yo naḥ pṛtanyādapa taṃ tamiddhatam̐ vajreṇa taṃ tamiddhatam dūre cattāya chantsadgahanam̐ yadinakṣat asmākam̐ śatrūnpari śūra viśvato darmā darṣīṣṭa viśvataḥ - iti śvo bhūta udayanīyo'tirātraḥ

Having released speech, they attend upon the āgnīdhra fire with: "You two, O Indra and Parvata, fighting in the forefront, strike down whoever battles against us; strike him down with the thunderbolt! Let the impenetrable thicket hide him if he flees far away; O hero, let the cleaver cleave through our enemies on every side!" On the following day is the closing atirātra.