Php 3:12

Php 3:12 Not as though I had already attained, either were already perfect, but I am pressing on, if I may lay hold of that for which I also was taken hold of by Christ Jesus.

Those are Paul's words. Let's put them into a simple thought: I have not reached the place where God wants me to be, but I'm going to keep trying until I get there.
Simply put, God has in mind what He wants for us, as Christians (if you're not Christian, this doesn't apply). He makes it known to us through various means what he wants for us. He puts the longing in your path; what are you going to do with it?