Śatapatha Brāhmaṇa ("of a hundred paths") 3.3.2.8

3.3.2.8

atra haike | tṛṇaṃ vā kāṣṭhaṃ vāvittvāpāsyanti tadu tathā na kuryātkṣatraṃ vai somo viḍanyā oṣadhayo 'nnaṃ vai kṣatriyasya viṭ sa yathā grasitamanuhāyācidya parāsyedevaṃ tattasmādabhyeva mṛśedvicitastvā vicinvantviti tadya evāsya vicetārasta enaṃ vicinvanti

Now some, on noticing any straw or (piece of) wood (among the Soma-plants), throw it away. But let him not do this; for--the Soma being the nobility and the other plants the common people, and the people being the nobleman's food--it would be just as if one were to take hold of and pull out some (food) he has put in his mouth, and throw it away. Hence let him merely touch it, with, 'Let the pickers pick thee!' Those pickers of his do indeed pick it.