Śatapatha Brāhmaṇa ("of a hundred paths") 2.3.2.9

2.3.2.9

tadyatraitatprathamaṃ samiddho bhavati | dhūpyata iva tarhi haiṣa bhavati rudraḥ sa yaḥ kāmayeta yathemā rudraḥ prajā aśraddhayeva tvatsahaseva tvannighātamiva tvatsacata evamannamadyāmiti tarhi ha sa juhuyātprāpnoti haivaitadannādyaṃ ya evaṃ vidvāṃstarhi juhoti

Now when it is first kindled, and there is as yet nothing but smoke, then indeed that(fire) is Rudra. And if anyone (Kshatriya) desires to consume food (belonging to others),--even as Rudra seeks after these creatures, now with distrust, now with violence, now in striking them down,--let him offer then: and, assuredly, he who, knowing this, offers then (when the fire has just been lighted), obtains that food.