In plain words
Those who eat what remains after yajña are freed from all sins; but those sinful people who cook only for themselves eat sin.
Word for word
Those who eat the remnant of yajña, being [such], are freed from all sins; but those sinful ones who cook for their own sake eat sin.
यज्ञशिष्टाशिनः सन्तो मुच्यन्ते सर्वकिल्बिषैःभुञ्जते ते त्वघं पापा ये पचन्त्यात्मकारणात्
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
ये पुनः —
देवयज्ञादीन् निर्वर्त्य तच्छिष्टम् अशनम् अमृताख्यम् अशितुं शीलं येषां ते यज्ञशिष्टाशिनः सन्तः मुच्यन्ते सर्वकिल्बिषैः सर्वपापैः चुल्ल्यादिपञ्चसूनाकृतैः प्रमादकृतहिंसादिजनितैश्च अन्यैः । ये तु आत्मम्भरयः, भुञ्जते ते तु अघं पापं स्वयमपि पापाः — ये पचन्ति पाकं निर्वर्तयन्ति आत्मकारणात् आत्महेतोः ॥ १३ ॥
In plain words
And those, on the other hand, who —
After completing the sacrifices to the gods, whatever food remains — called nectar itself — those whose habit it is to eat only that remainder are called 'eaters of the remains of sacrifice', and by being so, they are freed from every taint, every sin — even the small, unavoidable violences of daily household life, from the hearth and the rest, and whatever else arises from carelessness. But those who feed only themselves, who eat without ever offering first — what they eat is nothing but sin, and they themselves become sinners. These are people who cook, who go through all the motions of cooking, purely for their own sake, for themselves and no one else.
Close to the Sanskrit
But those who —
Having performed the sacrifices to the gods and so on, that remainder — food called nectar — to eat [it habitually] is whose nature: they [are] 'eaters of the remains of sacrifice'; being [so], they are released from all taints, all sins, [namely those] produced by the five 'slaughter-places' beginning with the hearth, and other [sins] born of violence and the like done through carelessness. But those who [are] self-feeders — who eat — they, indeed, [eat] sin, [and are] themselves sinners too — who cook, [who] perform cooking, for their own sake, for their own reason [i.e. for themselves alone].