The "first law" says that if there is no external force (a push or pull), things that are not moving will stay not-moving, and things that are moving will keep moving in the same way. Before, people thought that things would slow down and stop moving even if there was no force making them stop. Newton said this was wrong. Often, people say, "Objects that are not moving tend to stay not-moving, and objects that are moving tend to stay moving, unless acted upon by an outside force, such as gravity, friction, etc..."