וַיֵּ֥לֶךְ אִ֖ישׁ מִבֵּ֣ית לֵוִ֑י וַיִּקַּ֖ח אֶת־בַּת־לֵוִֽי׃
A certain member of the house of Levi went and took to wife a woman of Levi.
(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 Hebrew term containing אִישׁ, by employing a situation-oriented construal as outlined in this introduction, pp. 11–16.)
Depicting a situation schematically (as here) is a prototypical usage of אִישׁ as a situating noun.
The reference is specific, so the referent’s gender is germane. Yet that aspect is quickly evident from the predicated act of marrying a woman.
As for rendering into English, the NJPS ‘certain man’ nowadays sounds awkward, because the situating properties of man have somewhat dissipated. The revised rendering follows NJPS (and RJPS) in 2 Sam 16:5.