Śatapatha Brāhmaṇa ("of a hundred paths") 6.8.2.2

6.8.2.2

te cetayamānāḥ | etadapaśyannapa evainadabhyavaharāmāpo vā asya sarvasya pratiṣṭhā tadyatrāsya sarvasya pratiṣṭhā tadenatpratiṣṭhāpya yadatrāgneyaṃ tadadbhyo 'dhi janayiṣyāma iti tadapo 'bhyavāharaṃstathaivainadayametadapo 'bhyavaharati

While meditating, they saw this,--'Let us take it down to the water; for the water is the foundation of this universe: having settled it on that wherein is the foundation of this universe, we shall reproduce from out of the water what there is of Agni's nature in this (heap of ashes).' They then took it down to (and threw it into) the water; and in like manner does this (Sacrificer) now take it down to the water.