What does it really mean to call Jesus “Lord”? This study traces the biblical language behind God (Elohim), LORD (Yahweh), and Lord/Master (Adonai), following the thread from Job through the Old Testament and into the New. Along the way, we explore how the early Christians applied Yahweh-texts to Jesus and what “Lord” meant in their world—covenant allegiance, authority, surrender. The question isn’t just whether we believe in God, but whether we can say with Thomas: “My Lord and my God.”