The Greek noun biōsis is an abstract noun from the verb bioō (to live), meaning manner of life, way of living, or one's mode of existence. It appears once in the New Testament in Acts 26:4, where Paul describes his manner of life from youth as publicly known.
Paul's use of biōsis in his defense before Agrippa reveals his rhetorical strategy: appeal to observable history. His manner of life (biōsin) was no secret — the Jews who knew him from his youth in Jerusalem could testify. The word suggests that authentic faith produces a visible, consistent pattern of living — a biōsis that others can examine. This mirrors the broader New Testament teaching that faith is not merely internal but demonstrated in observable life patterns (James 2:18). Who you are is written in how you live.