nail (one's) colors to the mast

To refuse to cease or surrender. Because lowering a ship's flag was a customary indication of surrender, this nautical phrase emphasizes the resolve of a ship's crew. We will nail our colors to the mast and fight on—they will never capture us! We're going to have a tough time beating this team now that they are playing with such determination. I fear they've nailed their colors to the mast.