וַיִּחַר־אַ֥ף דָּוִ֛ד בָּאִ֖ישׁ מְאֹ֑ד וַיֹּ֙אמֶר֙ אֶל־נָתָ֔ן חַי־יְהֹוָ֕ה כִּ֣י בֶן־מָ֔וֶת הָאִ֖ישׁ הָעֹשֶׂ֥ה זֹֽאת׃
David flew into a rage against the man, and said to Nathan, “As GOD lives, the man who did this* deserves to die!
*Or “any man who has done this.”
(The above rendering comes from the RJPS translation, an adaptation of the NJPS translation. Before accounting for this rendering, I will analyze the plain sense of the אִישׁ term, by employing a situation-oriented construal as outlined in “Notes on Gender in Translation,” pp. 11–16.)
Many interpreters hold that David is treating Nathan’s depicted case as a real one that requires him to pass judgment. Another view is that David understands the case to be a parable—a hypothetical situation. This boils down to the question of whether his use of הָאִישׁ refers specifically to the aforementioned person in the story, or alternatively to a type—namely anyone who fits the stated criterion. (On such usage, see Biblical Hebrew Reference Grammar [2017] §24.4.4(4) [emphasis in original]: “The article is used generically to designate a class of persons of things that are definite in themselves.”)
The wording strongly supports the second view. Not only is the inclusion of the modifier הָעֹשֶׂה זֹאת unwarranted for a specific reference (because in that case the audience could be relied upon to identify the intended referent based on salience; cf. Gen 30:43), but also its participle form confirms that David is making a categorical statement—as befits a parable.
For further confirmation that the text’s ancient audience would likewise have understood David’s construal in this way, see Jeremy Schipper, “Did David Overinterpret Nathan’s Parable in 2 Samuel 12:1–6?” Journal of Biblical Literature 126.2 (2007): 383–407, here 384–86): “The parable does not have any of the typical features of a legal proceeding, such as specific details, witnesses, or testimony (cf. 1 Kgs 3:16–30).… The poetic style and vocabulary in vv. 1b–4 link the story more closely with proverbs and parables than with legal petitions.… Given Nathan’s use of proverbial language and lack of legal disguise, one has little reason to suppose that David does not see this story as [a] prophetic parable, requiring some allegorical interpretation.”
As for rendering into English, the NJPS ‘the man who did this’ implies that David is treating the case as a real one. The alternative rendering, which reflects the view that David treats the case as a parable, is borrowed from NLT; it is a natural way to make a spoken categorical statement. (Also, to allow for both interpretations, in the next verse I replace the auxiliary verb shall with must.)