Śatapatha Brāhmaṇa ("of a hundred paths") 9.2.3.37

9.2.3.37

sa vai śamīmayīm prathamāmādadhāti | etadvā eṣa etasyāmāhutyāṃ hutāyām prādīpyatodajvalattasmāddevā abibhayuryadvai no 'yaṃ na hiṃsyāditi ta etāṃ śamīmapaśyastayainamaśamayaṃstadyadetaṃ śamyāśamayaṃstasmācamī tathaivainamayametacamyā śamayati śāntyā eva na jagdhyai

He first puts on one of samî-wood (acacia suma). For at that time, when this oblation had been offered, he (Agni) was enkindled and blazed up. The gods were afraid of him, lest he might injure them. They saw this samî tree, and therewith appeased him; and inasmuch as they appeased (sam) him by that samî, it is (called) Samî; and in like manner this (Sacrificer) now appeases him by means of that samî (wood),--just with a view to appeasement, not for food.