(draw the sword and) throw away the scabbard
old-fashioned To approach or prepare for a conflict or military engagement with no intention of resolving it peacefully. We've seen the effects of having a leader who draws the sword and throws away the scabbard—that's the reason we've been in this war for nearly two decades. It won't benefit anyone if you throw away the scabbard as you head into this legal battle.
throw away the scabbard
abandon all thought of making peace. This expression derives from the proverb he who draws his sword against his prince must throw away the scabbard . It implies that the person in question has no choice but to fight