"Now some of you will say that the two are one and the same -..." — Kelly Long quote meaning

Now some of you will say that the two are one and the same - happiness and joy - but this is not so. Happiness is a feeling. Happiness is fleeting, dependent on the moment, the circumstances, even the weather. Joy is transcendent, enduring, and, in the biblical context, is not an emotion. Joy is an attitude of the heart. Joy brings us peace, a refuge in the midst of troubles. God gives us joy through His Spirit. But the enemy tries to steal your joy and give you temporary happiness instead. Now, is there anything wrong with being happy? Nee, but it cannot last. So, you may wonder why I bring up the difference between these two - it is simple really. [...] marriage is sacred before the Lord, a decision for a lifetime, but too often I think young people look upon it as a source of happiness. Do not look at marriage this way. See it as a reservoir of joy, a deep, welling spring that endures the icy blast of temper, the bite of an angry word, the void of loneliness in a heart hungry for talk when there is no response. [...] Seek joy in each other, not happiness.