Helm

The steering apparatus of a ship — the small piece by which a great vessel is turned — appears in James's letter as a "rudder," guided by a "helmsman."

A Small Rudder Turning a Great Ship

James draws on the imagery of seafaring to illustrate the disproportionate power of small things over large ones: "Look, the ships also, though they are so great and are driven by rough winds, are yet turned about by a very small rudder, where the impulse of the helmsman wills" (Jas 3:4). The piece is small; the ships it turns are great and storm-driven; the will that decides the turn belongs to the helmsman. A footnote glosses helmsman as literally "him who makes straight," and points the reader to John 1:23 for the underlying verb-image of straightening or making a straight way.