From the first paragraph of FM 1: The Army and the Profession of Arms:

First and foremost, the Army is Soldiers. No matter how much the tools of warfare improve, it is Soldiers who use them to accomplish their mission. Soldiers committed to selfless service to the Nation are the centerpiece of Army organizations. Everything the Army does for the Nation is done by Soldiers supported by Army civilians and family members. Only with quality Soldiers answering the noble call to serve freedom can the Army ensure the victories required on battlefields of today and the future.