We shall, for instance, be at rest. Sometimes we pray for rest from toil. Such rest is the product of the fulness of the Spirit. Joy is another product. Christian joy does not depend on circumstances, for it is beyond their reach and is abiding.
Happiness is like the surface of the sea.
If the weather is calm, the water is quiet. If storms rage and tempests tear, the ocean is tossed into mountainous billows, yet in the depths lie peace and stillness. The one is not affected by circumstances, and the other is. Only the fulness of the Spirit brings joy. This is not the love of sentiment or merely natural affection, but divine love, such as can be shed abroad in our hearts only by the Holy Spirit.