When Jesus saw their faith, he said to the paralytic, "Child, your sins are forgiven." Mk 2,5
Jesus has done a few miracles in chapter one of Mark's gospel.
They are all healing miracles and chasing out of the demons.
In this chapter (Chapter two) he does, yet, another healing miracle and
for the first time the element of faith comes to play.
But interestingly it is not the faith of the one who is healed.
When Jesus saw the faith of the four who were carrying the sick
he heals the one who is carried.
Here again it is Jesus who sees the faith of the four.
They have not expressed in anyway except in carrying
the sick with the intention of being healed.
They express this intention in a singular way
by bringing the sick close to Jesus
even by removing the roof of the house.
Faith expressed in an extraordinary way works miracle.
Also the one who is to be healed has to be near Jesus
even though he does not seem to express his faith in anyway.
It is because he is sick, that he has not expressed his faith or
he is not able to express it.
But he is brought close to Jesus.
That is why we ask others to pray for our intentions.
Prayers and faith of a third person can work wonders.
St. Augustine was converted on the prayer of his mother.
And there are many more examples.
Faith in GOD (here in Jesus) and closeness to Jesus
seem to be factors that work miracle.