The Law Code of Yājñavalkya 1.10.57

1.10.57

tato vaiśvadevārthabrāhmaṇasamīpe bhūmiṃ prādakṣiṇyena yavair anvavakīrya anantaraṃ taijasādibhājane sapavitrake kuśayugmāntarhite śaṃ no devīr abhiṣṭaya ity anayarcāpaḥ kṣiptvā yavo 'si dhānyarājo vā ityādinā mantreṇa yavān tato gandhapuṣpāṇi ca kṣpitvānantaraṃ arghyapātrapavitrāntarhiteṣu brāhmaṇahasteṣu yā divyā āpaḥ pṛthivi ityādinā mantreṇa viśvedevā idaṃ vo 'rghyam ity arghyodakaṃ vinikṣipet || 1.230 ||

Then, having scattered barley-grains around the ground clockwise near the Brahmins meant for the Viśvedevas; next, pouring water into a metallic or other vessel containing a purifying grass loop (sapavitraka) interlaid with a pair of kuśa blades, with the verse "May the divine waters be for our aid..."; and throwing in barley-grains with the mantra "You are barley, king of grains..." etc., and then perfumes and flowers; he should then pour the water of the guest offering into the hands of the Brahmins, which are covered with the purifying kuśa of the offering-vessel, with the mantra "O divine waters, [which flow] upon earth..." etc., saying, "O Viśvedevas, this is your guest offering (arghya)." // 1.230