Happiness is a by-product of the regular assembling of ourselves with believers of like faith. Happiness is a by-product of the ardent fervor of our spirits. Happiness is a by-product of the study of God's Word. Happiness is a by-product of the fear of God, by which we attain wisdom. Happiness is a by-product of a pure conscience toward God.
Happiness is a by-product of assurance of salvation.
Happiness is a by-product of trying to serve God in all that we do, even if we don't succeed. The people of the world, even some Christians, are always seeking that which seemeth right to a man. The people of this world cannot attain this true happiness because they are incapable of living a life in obedience to God. But True Christians have the power to attain this happiness if we walk after the Spirit and not after the flesh. If we must take up the cross and follow Him.