People have generalized almost every hard thing (especially relating to Jesus) as being impossible.
Impossible and hard should not be used interchangeably because they don't absolutely mean the same thing.
It is impossible means it is impossible but when it is hard, it means it is hard but possible.

It is hard but not impossible to be perfect.
It is hard but not impossible to live without sin.
It is hard but not impossible to follow in the footsteps of Jesus.
It is hard but not impossible to do away with lies even 'white lies'.
It is hard but not impossible to forsake all and follow Jesus.
It is hard but not impossible to hate ones life in this world.
It is hard but not impossible to call no man on earth father.

Hmm! Indeed it is hard to even understand many things in life