Newton's first law is the law of inertia stating that an object in motion stays in motion at the same speed unless acted on by an equal and opposite force and an object at rest stays at rest unless acted upon by an external force.
If a hockey puck is hit on ice (without friction), it will continue to move until friction or another force stops it. If a hockey puck is sitting in one place, the puck will not move until some external force moves it.
The motion of the hockey puck is a result of the sum of external forces on the hockey puck being unequal.
