2.3.27
सर्वनाम्नस्तृतीया च
Operational rule vidhi
After a सर्वनामस्थान -- सर्वादीनि सर्वनामानि (1.1.27), when it signifies the cause of an action and the word हेतु is used with it, the 3rd case-affix is used, as well as the 6th.
Word by word (padaccheda)
Target सर्वनाम्नः ṣaṣṭhī · ekavacanaSubstitute / term तृतीया prathamā · ekavacanaIndeclinable च avyaya
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
- Indeclinable An avyaya such as च "and", वा "optionally", न "not".
Full reading
सर्वनाम्नः तृतीया च
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
सर्वनाम्नः → तृतीया
Replace sarvanāmnaḥ with tṛtīyā. Inherited words (anuvṛtti) may add further conditions.
Commentary
After a सर्वनामस्थान -- सर्वादीनि सर्वनामानि 1.1.27, when it signifies the cause of an action and the word हेतु is used with it, the 3rd case-affix is used, as well as the 6th.
Ex. कस्य or केन हेतुना वसति 'for the sake of what does he live?' यस्य or येन हेतुना वसति ।
Vart:- When the words निमित्त or कारण are so used, almost all the case affixes may be employed; as किं निमित्तं or केन निमित्तेन or कस्मै निमित्ताय or कस्मान्निमित्तात् or कस्मिन् निमित्ते वसति. Similarly with the words karana and hetu. Here also the word हेतु does not mean the word-form hetu 1.1.68 but its synonyms also; as किं प्रयोजनं or केन प्रयोजनेन or कस्मै प्रयोजनाय &c., वसति.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.