Manava Dharmashastra 3.142

3.142

bhiṣajaḥ cikitsakāḥ | devalakāḥ pratimāparicārakāḥ | ājīvanasambandhenaitau pratiṣidhyete | dharmārthatve tu cikitsakadevalatvayornādoṣaḥ | māṃsavikrayiṇaḥ saunikāḥ | dvitīyāntapāṭhe pūrvaślokādākhyātānuṣaṅgaḥ | vipaṇena jīvantaḥ pratiṣiddhena pathena | pratiṣiddhāḥ panthā daśamādhyāye vakṣyante | tena ye jīvanti te| varjyāḥ | ubhayatra |
māṃsavikrayiṇastu dharmārthamapi niṣidhyante | yasya kenacinmāṃsamupahṛtam; anyasya ca tenārthaḥ, upahṛtamāṃsasyaca ghṛtena homopayoginā,—sa māṃsaṃ ghṛtena vinirmimīte,— bhavatyasaudharmārtho vinimayaḥ | vikrayaśabdavācyatā vinimayasyāpi bhavatītyata īdṛśā dharmārthamāṃsavikrayiṇo'pi pratiṣidhyante |

Healers, temple-attendants, meat-sellers and those living by trade,—these should be avoided at rites performed in honour of gods and Pitṛs.—(152)

Medhātithi’s commentary (manubhāṣya):
‘Healers physicians.

‘Temple-attendants’—those who attend upon idols.

These two are prohibited only as means of living. Healing and serving idols, when done entirely with a righteous motive (and not as a means of living), are not reprehensible.

‘Meat-sellers’—Butchers.

If we read these words with the Accusative ending, then they have to be construed with the verb of the preceding verse.

‘Those living by trade’—i.e., by improper trade; improper merchandise shall be described under Discourse 10,—those who live by such trade.

‘Should be avoided’—at both kinds of rites.

Meat-selling is reprehensible, even when done with a righteous motive. For instance, when one man has got meat and another man has need for it;—the former man who has got the meat stands in need of butter for oblations; and he exchanges his meat with the other man’s butter; this exchange is done ‘with a righteous motive,’ and exchange also is called ‘selling;’ hence those also become excluded who do such meat-selling, even with a righteous motive.—(152)