Śatapatha Brāhmaṇa ("of a hundred paths") 2.2.2.5

2.2.2.5

caturviṃśatiṃ dadyāt | caturviṃśatirvai saṃvatsarasyārdhamāsāḥ saṃvatsaro yajñaḥ prajāpatiḥ sa yāvāneva yajño yāvatyasya mātrā tāvatībhirdakṣayatyeṣā mātrā dakṣiṇānāṃ dadyāttveva yathāśraddham bhūyasīstadyaddakṣiṇā dadāti

He may give twenty-four; for twenty-four half-moons there are in the year, and the sacrifice, Pragâpati, is the year: thus as great as the sacrifice is, as large as its extent is, by so many (gifts) does he thereby invigorate it. Such is the measure of the priests' fees; but he may give more, according to (the depth of) his faith. The reason why he gives fees to the priests is this.