तीर्थवंशोपदेशः
Tīrtha-vaṃśa Upadeśa: Instruction on the Fruits of Sacred Waters
भरतश्रेष्ठ! जो ब्राह्मण श्राद्धकी समाप्ति होनेपर “अस्तु स्वधा” आदि तत्कालोचित वचनोंका प्रयोग नहीं करता है, उसे गायकी झूठी शपथ खानेका पाप लगता है ।।
bhīṣma uvāca | bharataśreṣṭha! yo brāhmaṇaḥ śrāddhasya samāptau “astu svadhā” ity-ādi tatkālaucitāni vacanāni na prayuṅkte, tasya gāvaḥ kṛtvā mṛṣāśapathasya pāpaṃ bhavati || yudhiṣṭhira! yasmin dine supātra-brāhmaṇaḥ prāpyate, dadhi ghṛtaṃ ca prāpyate, amāvāsyā-tithiḥ ca, araṇyajāni kandamūlaphalapīṭhāni ca labhyante, sa eva śrāddhasyottamaḥ kālaḥ ||
ビーシュマは言った。「おお、バーラタ族の最勝者よ。シュラーダ(śrāddha)の終わりに、ブラーフマナが『アストゥ・スヴァダー(astu svadhā)』などの時宜にかなった結句をただちに唱えないなら、牛について偽りの誓いを立てるに等しい罪を負う。おお、ユディシュティラよ。シュラーダを行う最上の時とは、まさにその日である——ふさわしい受供者たるブラーフマナを得、凝乳とギーを備え、新月の日に当たり、さらに森の産物、すなわち塊茎・根・果肉などがそろう日。これらの要件が一つに集まるとき、その機会そのものが吉時となる。」
भीष्म उवाच
Ritual dharma depends not only on intention but also on correct, timely speech and procedure: omitting the proper concluding formulae of śrāddha is treated as a serious ethical fault. Further, the ‘best time’ for śrāddha is pragmatically defined as the convergence of a worthy recipient and suitable offerings (including amāvāsyā and appropriate foods), emphasizing fitness and availability over rigid calendrical formalism.
In the Anuśāsana Parva’s instruction section, Bhīṣma continues advising Yudhiṣṭhira on dharma after the war. Here he gives specific guidance on śrāddha: the necessity of uttering the concluding words like “astu svadhā,” and the criteria by which a day becomes an excellent occasion for performing the rite.