The motto of the United States Marine Corps? What is its origin and significance?

The US Marine Corps -USMC is an amphibious assault combat unit under the US Admiralty. Its main responsibility is to use the US Navy's ships to quickly reach crisis-ridden places around the world and carry out combat missions. The US Marine Corps is the earliest elite force in the world and the main combat force of the US rapid reaction force, with a long history. Administratively, the U.S. Marine Corps and the U.S. Navy belong to the U.S. Navy Department under the U.S. Department of Defense. Their ranks and names are the same as those of the Army and Air Force, and they belong to an independent service of the U.S. Army. The Marine Corps has also established the Guard Force (MCESG) in the State Council, which is responsible for the security of the American Embassy. But usually, it is a service that can only perform various training and combat tasks alone.