וַיָּבֹא֙ הַמַּגִּ֔יד אֶל־דָּוִ֖ד לֵאמֹ֑ר הָיָ֛ה לֶב־אִ֥ישׁ יִשְׂרָאֵ֖ל אַחֲרֵ֥י אַבְשָׁלֽוֹם׃
Someone came and told David, “The loyalty of Israel’s force has veered toward Absalom.”
(The above rendering comes from the RJPS translation—an adaptation of the NJPS translation—as slightly modified in May 2024. 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.)
When a referring expression includes אִישׁ, that noun prototypically marks its referent’s defining participation in the depicted situation. This remains true when אִישׁ is in construct with a group name, such as אִישׁ יִשְׂרָאֵל֙. Here, in the context of looming intragroup hostilities, it labels the militia in terms of their being a constitutive party to the pending coup d’état. The militia’s members are construed as a unit—hence the singular noun. This usage regards them as one of the two opposing sides. This is one of the instances where a “collective” construal of אִישׁ yields a more informative text than does an individual construal. Indeed, the singular term immediately prompts the king to flee for safety, as if its referent poses an overwhelming threat (see next verse).
On the meaning of this conventional usage in the context of hostilities, see further my comment at Josh 10:24.
As for rendering into English, see my comment at Josh 10:24. Meanwhile, the fact that women are not in view is self-evident from the military context.