Consider a hammer. It's designed to hit nails. That's what it was created to do. Now imagine that the hammer never gets used: just sit in the toolbox. The hammer doesn't care.
But now, imagine the same hammer with a soul, a self-conciousness. Days by days go by him remaining in the box. He feels funny inside, but he's not sure exactly why. Something is missing, but he doesn't know what it is.
One day, someone pulls him out of the toolbox and uses him to break some branches for the fire place. The hammer is exhilarated. Being held, being weilded, hitting the branches - the hammer loves it. At the end of the day though, he is still unfulfilled. Hitting the branches was fun, but it wasn't enough. Something is still missing.
In the days that follow, he's used more often. He reshapes the hubcap, knocks a table leg back into the place. Still, he's left unfulfilled. So he longs for more action. He wants to be used as much as possible to knock things around, to break things, to blast things, to dent things. He figures that he just hasn't had enough of these events to satisfy him. More of the same, he believes, is the solution to his lack of unfulfilment.
Then, one fine day, someone uses him to hit a nail. Suddenly the light come in his hammer soul. He now understands what he was truly desinged for. He was meant to hit nails. All the other things he hit pale in comparison. Now he know what his hammer soul was searching for all long.
As human being, we are created by Allah for God-servant relationship. Being in that relationship is the only thing that will ultimately satisfy our souls. Until we come to know Allah, we've had many wonderful experiences, but we still haven't hit a nail. We've been used for some noble purposes, but not the one we were ultimately designed for, not the one through which we will find the most fulfilment.
A relationship with Him is the only thing that will quench our soul's longing. Before we come to know Him, our souls are 'hungry' and 'thirsty' . In life we try to 'eat' and 'drink' all kind of things to satisfy our hunger and thirst, yet they still remain.
We are just like the hammer. We don't realize what will end the emptiness, the lack of fulfilment in our lives. Usually, when we put our relationship with Allah aside or try to find fulfilment in something other than Him, we can never get enough of that thing, we keep 'eating' and 'drinking' more and more, erroneuosly thinking that 'more' is the answer to the problem, yet we are never ultimately satisfied.
Our greatest desire is to know Allah, to have relationship with Allah. Why? Because that's how we've been designed. So, have you hit your nail yet..? Treasure for it more!