The Law Code of Yājñavalkya 1.10.87

1.10.87

annaṃ pāṇitale dattaṃ pṛthag aśnanty abuddhayaḥ |
pitaras tena tṛpyanti śeṣānnaṃ na labhanti te ||
yac ca pāṇitale dattaṃ yac cānyad upakalpitam |
ekībhāvena bhoktavyaṃ pṛthagbhāvo na vidyate ||
iti | 1.236 || 1.237 ||

"The ignorant eat separately the food given into the palm of their hands; / The ancestors are satisfied by this, but they do not obtain the rest of the food.
Both what is given into the palm of the hand and whatever else is prepared / Must be eaten together as one; there is no division." // (1.236–1.237)