Joy. What does joy mean to you?
Is it the happiness you experience when you see your favorite team win the Super Bowl? Is it the pleasure of a fine meal? This is all joy, but it's not the Christian joy. I don't mean that it's sinful to find pleasure in these and other experiences - just that it's not how God defines joy.
And, interestingly enough, it's not how C.S. Lewis describes joy. Joy is the yearning for ... the longing for ... something else.
I call it Joy, which is here a technical term and must be sharply distinguished both from Happiness and Pleasure. Joy (in my sense) has indeed one characteristic, and one only, in common with them; the fact that anyone who has experienced it will want it again... I doubt whether anyone who has tasted it would ever, if both were in his power, exchange it for all the pleasures in the world. But then Joy is never in our power and Pleasure often is.” (C.S. Lewis)
Joy is the longing for something that we experience for only a moment. We cannot hold onto it. It is not an end in itself. When we make it the goal, rather than the goal being what we yearn for, we cannot reach it (the joy or the goal). Complicated, isn't it?
Joy is never ours to achieve. It is a gift from God - a spiritual gift. Lewis, I think, if I understand correctly, would say that joy is the longing for God. It is what we experience for just a moment when we are in God's presence. It is not something we create - it is fleeting. Try to hold onto it and it slips away. Try to recreate it, and you'll fail. Open yourself up to sanctifying grace; find joy.