Shatapatha Brahmana 5.5.5.18

5.5.5.18

trīṇi vāsāṃsyadhvaryave | tanute vā adhvaryuryajñaṃ tanvate vāsāṃsi tasmāttrīṇi vāsāṃsyadhvaryave gāmagnīdhe

Three garments (he gives) to the Adhvaryu;--for the Adhvaryu 'spreads' the sacrifice, and the garments spread themselves (over the body): therefore (he gives) three garments to the Adhvaryu. A bullock (he gives) to the Agnîdh.