According to Hooke's Law, $F=-kx$ where $F$ is the restoring force, $k$ is the spring constant and $x$ is the length of extension/compression.
When an applied force compresses a spring, a restoring force will act in the opposite direction.
When a spring is compressed and is in equilibrium (not extending/compressing), the restoring force should be equal to the applied force since the resultant force is 0 and the acceleration is 0. (Thus the spring is not extending/compressing)
However, the act of compressing a spring will require the applied force to be greater than the restoring force even at an infinitesimally small time interval, am I wrong?
Is it more correct to say that $F=kx$ where $F$ is the applied force or $F=-kx$ where $F$ is the restoring force? I think that $F=-kx$ the better option, but I'm pretty confused here. Does it matter at all?