Śatapatha Brāhmaṇa ("of a hundred paths") 9.1.2.2

9.1.2.2

adbhiḥ pariṣiñcati | śāntirvā āpaḥ śamayatyevainametatsarvataḥ pariṣiñcati sarvata evainametacamayati triṣkṛtvaḥ pariṣiñcati trivṛdagniryāvānagniryāvatyasya mātrā tāvataivainametacamayati

With water he sprinkles him,--water is a means of appeasing (soothing): he thus appeases him thereby. He sprinkles him all over; he thus appeases him all over. Thrice he sprinkles,--threefold is Agni: as great as Agni is, as great as is his measure, with so much he thus appeases him.