(Whitney §267-268)
The third (तृतीय) case is the instrumental. It is most often translated as “with” or “by”. That is, it is used to denote adjacency, accompaniment, and association as well as denoting the agency or means by which something occurs. Examples of accompaniment are:
अग्निर् देवेभिर् आ गमत्। “May Agni together with the gods come here.”
कथयन् नैषधेन। “Talking with Niṣhadha.“
Examples of the instrumental as agency or means are:
भद्रम् कर्णेभिः शृणुयाम। “May we hear with our ears what is auspicious.”
शस्त्रेन निधनम्। “death by sword”
केचित् पद्भ्याम् हता गजैः। “Some were killed by elephants with their feet“ (double accusative, agency and means)
Agency is also expressed by the instrumental as the subject of a passive verb. Thus:
सा यमेन दत्ताम् कण्ठिकाम् धारयति। “She wears a necklace given to her by Yama.”
व्याधेन जालम् विस्तीरणम्। “A net was laid out by the hunter.“
Other special uses of the instrumental include:
- Accordance, equality, and likeness
- Price
- Medium
- Time passed
- Part of the body that bears something
- Special phrases
- Instrumental absolute
समम् ज्योतिः सूर्येन “a brightness equal with the sun”
दशभिः क्रीणाति धेनुभिः। “He buys with ten cows.“
ते च कालेन महता यौवनम् प्रतिपेदिरे। “And over a long time they reached adolescence.“
कुक्कुरः स्कन्धेनोऽह्यते। “A dog is carried on the shoulder.“
बहुना किम् प्रलापेन। “What is the use of talking so much?“
न त्वयाऽत्र मयाऽवस्थितेन काऽपि चिन्ता कार्या। “With me at hand, you need feel no anxiety whatsoever on this matter.“
In the last example the instrumental absolute is: मया अविस्थितेन “with be standing by”.