Śatapatha Brāhmaṇa ("of a hundred paths") 11.5.4.18

11.5.4.18

tadāhuḥ na brahmacārī sanmadhvaśnīyādoṣadhīnāṃ vā eṣa paramo raso yanmadhu nedannādyasyāntaṃ gacānītyatha ha smāha śvetaketurāruṇeyo brahmacārī sanmadhvaśnaṃstrayyai vā etadvidyāyai śiṣṭaṃ yanmadhu sa tu raso yasyedṛkśiṣṭamiti yathā ha vā ṛcaṃ vā yajurvā sāma vābhivyāharettādṛktadya evaṃ vidvānbrahmacārī sanmadhvaśnāti tasmādu kāmamevāśnīyāt

And they also say, 'He who is a Brahmakârin should not eat honey, lest he should reach the end of food, for honey, doubtless, is the utmost (supreme) essence of plants.' But Svetaketu Âruneya, when eating honey, whilst he was a student, said, 'This honey, in truth, is the remainder (essential part) of the triple science (the Vedas), and he, indeed, who has such a remainder, is an essence.' And, indeed, if a Brahmakârin, knowing this, eats honey, it is just as if he were to utter either a Rik-verse, or Yagus-formula, or a Sâman-tune: let him therefore eat freely of it.