Śatapatha Brāhmaṇa ("of a hundred paths") 7.2.4.7

7.2.4.7

yadvevodacamasānninayati | etadvā asmindevāḥ saṃskariṣyantaḥ purastādapo dadhustathaivāsminnayametatsaṃskariṣyanpurastādapo dadhāti

And, again, why he pours out jarfuls of water;--at that time the gods, being about to put him (Agni-Pragâpati) together, in the first place put water into him; and in like manner does this one now, being about to put him together, in the first place put water into him.