Bhagavad Gita: Chapter 2/Verse 32

यदृच्छया चोपपन्नं स्वर्गद्वारमपावृतम् ।
सुखिनः क्षत्रियाः पार्थ लभन्ते युद्धमीदृशम् ॥२- ३२॥

yadṛcchayā copapannaṃ svargadvāramapāvṛtam ।

sukhinaḥ kṣatriyāḥ pārtha labhante yuddhamīdṛśam ॥2- 32॥

And by chance the warriors possessed of happiness reached the opened gate of heaven, they obtain such by the nature of war, O son-of-Prithā. 


Word-for-word translations

yadṛcchayā (feminine gender, instrumental, singular) = by chance

ca (conjunction) (indeclinable) = and

upapannam (past passive participle) (accusative, singular) = reached

svargadvāram (accusative, singular) = gate of heaven 

apāvṛtam (adjective) (past passive participle) (accusative, singular) = opened


sukhinas (adjective) (accusative, plural) = possessed of happiness 

kṣatriyās (nominative, plural) = warriors

pārtha (vocative, singular) = O son-of-Prithā (epithet of Arjuna)

labhante (present tense, 3rd person, plural) = they obtain

yuddham (adverbial usage of accusative case) (indeclinable) = by the nature of war

īdṛśam (adjective) (accusative, singular) = such 



Commentary 

I really feel the previous translations translate this verse based on their philosophical persuasions about war and gaining the "opened gate of heaven" by the nature of war. Previous translations agree on the first part of the verse, but the second part of the verse there are differing interpretations to the point that it does not make grammatical sense. The last three words, which are the point on contention are grammatically clear. "They obtain" meaning the warriors, "such" meaning "the opened gate of heaven", and "yuddham" which is an accusative case meaning "by the nature of war". Now the accusative case can be used adverbially in this context on the word "such" meaning "they obtained the opened gate of heaven by the nature of war". That makes "yuddham" an indeclinable by being an adverb. 

The whole philosophical point in this verse and in the previous verses is that one should do their duties to the best of their abilities because that is one's role, whatever role that may be. Everyone has their part and it must be played out. The first part of the verse says "warriors, by chance, can reach the open gate of heaven". That means, according to the philosophy in this text, that killing in war is not an abomination for a warrior conducting his/her duty as the slayer or the slain. Being the slayer or slain is irrelevant in the grand scheme of things, per a previous verse.