From this Jesus is telling us that if we keep
our faith (because it is our faith that makes
us whole or brings the answers) we will
received the answer.

It seems like many times when we pray if
our need is immediate, urgent and/or grave,
while we are waiting for the manifestation
of the answer, we see others around us getting
theirs answered. And we get to thinking that
we will not get ours, that it's hopeless or even
too late.

We have to battle the devil over what we see,
hear and feel (our senses) and do as Jesus said
fear not, believe only.