Bhagavad Gita · Chapter 3: The Path of Action
Bhagavad Gita 3.13
यज्ञशिष्टाशिनः सन्तो मुच्यन्ते सर्वकिल्बिषैः ।
भुञ्जते ते त्वघं पापा ये पचन्त्यात्मकारणात् ॥
yajñaśiṣṭāśinaḥ santo mucyante sarvakilbiṣaiḥ | bhuñjate te tvaghaṃ pāpā ye pacantyātmakāraṇāt ||
The good, who eat what remains after sacrifice, are freed from all sins. But the wicked, who cook only for themselves, eat sin.
Modern context
Those who share first and eat what is left are free of fault; those who cook only for themselves 'eat sin'. The household rule behind this was to feed the gods, guests, the needy and animals before sitting down oneself. The wider principle is to take one's own share after others have been provided for.