Acre

The acre, in the UPDV, is a rough land-measure used twice in scripture — once to bound the small piece of ground in which Jonathan strikes his first blow against the Philistines, and once to set the meager yield of a vineyard under judgment.

Measure of a Battle's Ground

The first use marks the close confines of Jonathan's surprise attack: "And that first slaughter, which Jonathan and his armorbearer made, was about twenty men, within, as it were half a furrow's length in an acre of land" (1Sa 14:14). The "half a furrow's length in an acre" sets the killing inside a tight patch of plowable ground, naming twenty men struck down in a space no larger than half a plowman's run.

Measure of a Vineyard's Yield

The second use sets the acre against the harvest in Isaiah's vineyard-oracle: "For ten acres of vineyard will yield one bath, and a homer of seed will yield [but] an ephah" (Isa 5:10). Ten acres of vineyard producing only a single bath, and a homer of seed returning only an ephah, names the cursed reduction of the land's yield against its expected measure.