Shatapatha Brahmana 11.5.6.7

11.5.6.7

medāahutayo ha vā etā devānām yadatharvāṅgirasaḥ sa ya evaṃ vidvānatharvāṅgiraso'harahaḥ svādhyāyamadhīte medāahutibhireva taddevāṃstarpayati ta enaṃ tṛptāstarpayanti yogakṣemeṇa prāṇena re

And, verily, the (texts of the) Atharvâṅgiras are fat-offerings to the gods; and whosoever, knowing this, studies day by day the (texts of the) Atharvâṅgiras for his lesson, satisfies the gods with fat-offerings; and, being satisfied, they satisfy him by security of possession, by life-breath, by seed, by his whole self, and by all auspicious blessings; and rivers of ghee and rivers of honey flow for his Fathers, as their accustomed draughts.