Shatapatha Brahmana 9.1.1.7

9.1.1.7

te prjāpatimabruvan | asmādvai bibhīmo yadvai no 'yaṃ na hiṃsyāditi so 'bravīdannamasmai sambharata tenainaṃ śamayateti tasmā etadannaṃ samabharañcatarudriyaṃ tenainamaśamayaṃstadyadetaṃ śataśīrṣāṇāṃ rudrametenāśamayaṃstasmācatadyadetaṃ śataśīrṣāṇāṃ rudrametenāśamayaṃstasmācataśīrṣarudraśamanīyaṃ śataśīrṣarudraśamanīyaṃ ha vai tacatarudriyamityācakṣate paro 'kṣam paro 'kṣakāmā hi devāstathaivāsmā ayametadannaṃ sambharati śatarudriyaṃ tenainaṃ śamayati

They spake unto Pragâpati 'We are afraid of this one, lest he should hurt us!' He spake, 'Gather food for him, and appease him therewith!' They gathered for him that food, the Satarudriya (offering), and thereby appeased him; and inasmuch as they thereby appeased (sam) the hundred-headed (satasîrsha) Rudra, it is called Satasîrsharudrasamanîya,--and satasîrsharudrasamanîya, doubtless, is what they mystically call Satarudriya, for the gods love the mystic. And in like manner does this (Sacrificer) now gather for him that food, the Satarudriya, and appease him thereby.