Come and Take It

During the American Revolution at Fort Morris in 1778, the British tried to overtake the fort in Sunbury, GA. Col. McIntosh's response included this line: "As to surrendering the fort, receive this laconic reply: COME AND TAKE IT!". Amazingly, the British retreated only to return the next year with more troops.
It was most famously used during the Texas Revolution in 1835 at the Battle of Gonzales. The battle was over a cannon that the Mexican authorities had given the town to protect themselves from frequent Comanche raids. When the state started to revolt, the Mexican troops asked for the cannon back to which they refused. During the battle, the Texans raised a homemade white banner with an image of the cannon painted in black in the center, over the words "Come and Take It"