Śatapatha Brāhmaṇa ("of a hundred paths") 5.3.4.13

5.3.4.13

atha yā ātapati varṣanti | tā gṛhṇāti sūryavarcasa stha rāṣṭradā rāṣṭram me datta svāhā sūryavarcasa stha rāṣṭradā rāṣṭramamuṣmai datteti tābhirabhiṣiñcati varcasaivainametadabhiṣiñcati sūryavarcasamevainametatkaroti medhyā vā etā āpo bhavanti yā ātapati varṣantyaprāptā hīmām bhavantyathainā gṛhṇāti medhyamevainametatkarotyetā vā ekā āpastā evaitatsambharati

He then catches such (water) as it rains while the sun shines, with, 'Lustrous as the sun ye are, bestowers of kingship: bestow ye kingship on me, hail!--Lustrous as the sun ye are, bestowers of kingship: bestow ye kingship on N.N.!' With this (water) he sprinkles: it is with lustre he thereby sprinkles him, and lustrous as the sun he thereby makes him. And pure indeed is such water as it rains while the sun shines, for before it has reached this (earth), he catches it: he thus makes him pure thereby. This is one kind of water: it is that he now brings.