Shatapatha Brahmana 11.4.2.19

11.4.2.19

sa hovāca adhvaryavā vai no'krukṣa ete vai te srucau ye tvaṃ saṃvatsaraṃ nāśaka ādātuṃ yadvai tvāhametayoranuśiṣyām pra prajayā paśubhirjāyethā abhi svargaṃ lokaṃ vaheriti

He (Ayasthûna) said, 'Adhvaryu, thou hast insulted us; and there now are those two spoons which, for a whole year, thou hast not been able to take up (in the proper manner): if I were to instruct thee in (the use of) them, thou wouldst become multiplied in offspring and cattle, and wouldst lead (the Sacrificer) to heaven.'