The phrase "person by person" is an idiom meaning each person. The persons in this sentence were the leaders of their households. Alternate translation: "He brought near each person of the clan of the Zerahites" or "From the clan of the Zerahites, he brought near each man who was the leader of his household" (See: [[rc://en/ta/man/jit/figs-idiom]] and [[rc://en/ta/man/jit/figs-explicit]])