plowshare

A sharp iron blade attached to the beam of a plow. Lacking rudimentary iron technology, Israelites of the early monarchical period (ca. 1020–1000 BCE) took plowshares for sharpening to the Philistines (1Sam 13:19-23). As instruments that can only be used in times of peace, they are contrasted with swords, also made of iron, which are instruments of war; turning swords into plowshares demonstrates peace (Isa 2:4; Mic 4:3). In (Joel 3:10), however, the process is reversed.