Newton's first law of motion gives an insight to this problem, if an object stays in its position of either motion or rest, it can only change its current of either motion or rest is by applying an external force on it.
If an object is resting on a table, there is a normal force acting perpendicular to the object and at the same, there is the gravitational force acting on the object in the perpendicular direction opposite to the direction of the normal force
Hence, these two forces cancel and the resultant force will be zero. so it is in rest and it moves only when the resultant force is non zero.
