Śatapatha Brāhmaṇa ("of a hundred paths") 11.2.3.7

11.2.3.7

tadvā ada āgneyyāmiṣṭā udyate yathā tadṛṣibhyo yajñaḥ prārocata taṃ yathātanvata tadyajñaṃ tanvānānṛṣīngandharvā upaniṣeduste ha sma saṃnidadhatīdaṃ vā atyarīricannidamūnamakranniti sa yadaiṣāṃ yajñaḥ saṃtasthe'thaināṃstaddarśayāṃ cakruridaṃ vā atyarīricatedamūnamakarteti

There, on the occasion of the offering to Agni, it has been told how the sacrifice then pleased the Rishis, and how they performed it. Now, when the Rishis were performing the sacrifice, the Gandharvas came nigh to them. They looked on, thinking, 'Here, surely, they have done too much,--here they have done too little.' And when their sacrifice was completed, they pointed it out to them, saying, 'Here, surely, ye have done too much,--here ye have done too little.'