When you encounter the phrase "be it" in formal writing, such as "be it lust or necessity," you are looking at a classical grammatical structure used to show concession. Instead of relying on modern conjunctions like "whether," "if," or "though," this construction relies on the subjunctive mood to establish a hypothetical condition. It allows a writer to present multiple possibilities or alternatives seamlessly, elevating the prose to a highly formal and literary register.

The mechanics behind this expression are straightforward but elegant. It utilizes the bare infinitive form "be" and subjects it to syntactic inversion with the pronoun "it." By flipping the verb and the subject, the sentence bypasses the need for a conjunction entirely. While the everyday indicative "it is" states a definite reality, the inverted subjunctive "be it" introduces a conditional concession, meaning "regardless of whether it is."