Śatapatha Brāhmaṇa ("of a hundred paths") 7.2.4.13

7.2.4.13

atha sarvauṣadhaṃ vapati | etadvai devā abruvaṃścetayadhvamiti citimicateti vāva tadabruvaṃste cetayamānā annameva citimapaśyaṃstāmasminnadadhustathaivāsminnayametaddadhāti

He then sows all (kinds of) herb (-seed);--for the gods then said, 'Meditate ye!' whereby doubtless they meant to say, 'Seek ye a layer!' whilst meditating, they saw food to be a (suitable) layer, and put that on (or, into) him (Agni); and in like manner does this one now put it into him.