at swords' points
Combative, quarrelsome, or belligerent. I'm not surprised that those two are arguing already—they're always at swords' points.
at sword's point
Also, at swords' points. Antagonistic, hostile, as in Father and son were at swords' points. Dating from the days when swords were used to settle quarrels, the idiom today generally signifies only a bitter quarrel.