Isaiah's prophecy — "they shall beat their swords into plowshares" — made the ploughshare the universal symbol of peace and agricultural renewal, the warlike instrument transformed into the instrument of cultivation; A poet might write "the ploughshare went into the earth like an argument that brooked no reply, turning the year's old surface under, committing the field to a new season's logic"; In pastoral poetry the ploughshare represents the transformative act of cultivation — the first turning of the earth that changes wild land into productive field, the original act of agricultural civilization; Burns, himself a farmer, attends to the ploughshare with technical respect in his agricultural verse — the implement that breaks open the Scottish clay, making the land available for the year's seed; The ploughshare's relationship to the sword — both are iron blades that cut, one destroying and one creating — makes it the central image in poetry about the relationship between war and agriculture, the peace that allows cultivation to replace violence; Contemporary peace poetry continues to invoke the ploughshare in its Isaian sense, the ancient agricultural tool carrying the full weight of the prophetic tradition's vision of a world where the instruments of violence are remade into the instruments of feeding.