Shloka 58
Adhyāya 166: Kṛtaghna-doṣa (कृतघ्नदोषः) — the fault of ingratitude and the limits of expiation
श्वृवराहखरान् हत्वा शौद्रमेव व्रतं चरेत् मार्जारचाषमण्डूकान् काकं व्यालं च मूषिकम्
śvṛvarāhakhārān hatvā śūdram eva vrataṃ caret mārjāracāṣamaṇḍūkān kākaṃ vyālaṃ ca mūṣikam
ビーシュマは言った。「猪と驢馬を殺したなら、シュードラの戒（ヴラタ）を行うべきである。同様に、猫、チャーシャ鳥（cāṣa）、蛙、烏、蛇、鼠を殺した場合も、同じくその戒を行うべきである。」
भीष्म उवाच
Educational Q&A
The verse is a prescriptive rule framed as part of Bhīṣma’s dharma-instruction: it links specific acts (here, the killing of certain animals) with undertaking a particular observance (vrata) associated with the Śūdra. In context, such lines function as normative or expiatory injunctions within varṇa- and conduct-discussions, emphasizing regulated behavior and the idea that actions entail prescribed disciplines.
In Śānti Parva, Bhīṣma instructs Yudhiṣṭhira on dharma after the war. This verse occurs within a didactic sequence of rules and observances, where Bhīṣma enumerates specific prescriptions—here listing animals and stating that after killing them one should undertake a stated vrata—reflecting the text’s broader concern with codifying conduct and consequences.