Śatapatha Brāhmaṇa ("of a hundred paths") 7.5.2.45

7.5.2.45

sa yaḥ sa prajāpatirvyasraṃsata | ayameva sa yo 'yamagniścīyate 'tha yā asmāttā āpa āyannetāstā apasyāstadyadetā upadadhāti yā evāsmāttā āpa āyaṃstā asminnetatpratidadhāti tasmādetā atropadadhāti

Now the Pragâpati who became disjointed is this very Agni who is now being built up; and the water (âpah) which went from him is these very Apasyâh;--hence when he lays them down, he thereby puts back into him that very water which went from him: therefore he now lays these down.