Consider the acceleration of a moving object that comes to a stop:
Acceleration = (change in speed) / (time for the change)
The "time for the change" is in the denominator of the fraction,
so the shorter the time is, the greater the acceleration is.
In the limit, as the time for the change gets closer to zero,
the acceleration gets closer to infinity.
Now consider what force is required to produce a certain acceleration.
Force = (mass) x (acceleration) .
The mass of the object is constant. So the more acceleration
you want to give it, the more force you need.
As the desired acceleration gets closer to infinite, so does
the force required in order to produce it.
In order to bring a moving object to an instantaneous stop,
an infinite force would be needed. None are available.
