Śatapatha Brāhmaṇa ("of a hundred paths") 2.4.2.7

2.4.2.7

tadvā etat | māsi māsyeva pitṛbhyo dadato yadaivaiṣa na purastānna paścāddadṛśe 'thaibhyo dadātyeṣa vai somo rājā devānāmannaṃ yaccandramāḥ sa etāṃ rātriṃ kṣīyate tasminkṣīṇe dadāti tathaibhyo samadaṃ karotyatha yadakṣīṇe dadyātsamadaṃ ha kuryāddevebhyaśca pitṛbhyaśca tasmādyadaivaiṣa na purastānna paścāddadṛśe 'thaibhyo dadāti

Now that (lustre) indeed belongs to him who presents (food) to the fathers once a month. When that (moon) is not seen either in the east or in the west, then he presents (food) to them; for that moon doubtless is king Soma, the food of the gods. Now during that night (of new moon) it fails them, and when it fails, he presents (food to them), and thereby establishes concord (between the gods and fathers). But were he to present (food) to them when it is not failing, he would indeed cause a quarrel between the gods and fathers: hence he presents (food) to them when that (moon) is not seen either in the east or in the west.