Joy is prayer; joy is strength: joy is love; joy is a net of love by which you can catch souls.
If you have ever been told that you are 'full of it', I doubt anyone meant it as a compliment! In fact, it was probably meant to be a means of point out some ridiculous idea you had, or that you are just full of yourself over some matter. It was said as a 'slam' on your character or behavior, not a compliment. When God looks at us and sees us as full of his joy, his words of encouragement are just that - encouragement to fill us up just a little more with the 'good stuff' he has prepared for our lives. What God desires most for us is that we be 'full' - not with ourselves - but with him. In turn, the joy of the Lord begins to overflow from our lives, touching the lives of others, so that what we are 'full of' becomes a means of blessing.
Be full of joy always because you belong to the Lord. Again I say, be full of joy! (Philippians 4:4)
How is it we can be 'full of joy'? It comes in remembering whose we are - who we belong to. If you belong to Jesus, you are full of his grace. You are overflowing with his peace. Your life is filled to the brim with his love. Maybe those things aren't what some would call 'joy', but if you begin to combine the ingredients of his love, grace, and peace, your heart gets pretty doggone joy-full! When we 'belong', that which we 'belong to' begins to permeate every part of our being. When I first went into the military at the age of 18, I actually lived and breathed being a part of our country's defenses. It permeated my whole being so that I even stood taller, somehow making me walk a little more determined with each step I took. It is possible to be 'filled' because we allow something to so 'permeate' our being that it becomes the very thing we live and breathe.
When that object of 'infilling' is Christ himself, we are certain to have the very 'ingredients' that lead to us being 'filled with joy'. Did you realize joy stems from having placed a great value on what becomes the source of your delight? The 'value' you place in whatever that source of your delight is determines the amount of joy your heart and mind is filled with! If you value your money, your source of delight is something that will fritter away over time, especially if you put it in something as volatile as the stock market. If you value a vehicle that is your 'dream car', you might find great delight in it while it is running well, but when it begins to suffer from the inevitable breakdown of parts, where will your joy be then? Joy is found in more than the 'object' - it is found in the delight we place in that object.
When the object of our delight is Christ, we are placing our delight in something that is unchangeable. His love and grace don't change - our appreciation of them might over time, but his love and grace remain consistent for all time. His peace is as reliable today as it was yesterday, yet we may not appreciate the fullness of that peace equally at all times. It isn't that what 'makes us full' has changed, it is that we find our need for these things vacillates over time. We might need a little more of the sense of his love right now because we are feeling kind of down on ourselves, or that we are not as 'lovable' as we should be right now. We could need to have a huge infilling of his grace because we have been trekking down paths that have led us to places of compromise in our lives. Regardless of the need, the filling comes from exactly the same source!
Be full of joy - not of yourself, or the circumstances, or the momentary and fleeting privilege we enjoy. Be full of that which never changes, is always consistent, and is ever there in our lives. Be full of Christ and in so choosing to be 'filled' you will find peace unimaginable, love deeper than you've experienced before, and grace beyond your wildest dreams. Joy comes not in the 'thing' we have, but in the 'one' who fills us with all these things. Just sayin!