I believe many Christians today get hung up on the word "happiness". They think that God wants Christians to have a deep inner joy, but happiness, on the other hand, is a word for the worldly. They don't especially think that God wants them to be happy.
The following is a part of an e-mail I wrote to a fellow colleague as we discussed these things. I thought you might benefit from it also:
Recently I have been studying up a little bit on happiness/ gladness as presented in the Bible. Often times the word, "blessed" is used for deep and full joy/happiness. For example:
1 Tim. 1:11 "in accordance with the gospel of the glory of the blessed God with which I have been entrusted."
I think most people skip over this word, "blessed", as simply meaning "serene" or even as "recluse". I used to.
"Blessed" here means, "fully satisfied", "possessing the characteristic of deity". God, by definition is simply fully satisfied and full of deep and overflowing joy. It seems our word "enthusiasm" also comes from the two words, "en" and "theos", meaning the one who is enthused is literally, "IN GOD"! It is the glory of God (as we see in the above verse) to be the only one who can do all things, and thus is by definition God is a deeply satisfied, happy, joyful God. He chooses to take on our pain, but even over this He is sovereign. We can (and should) take on God's deep satisfaction, because we are in the Almighty God through Christ. All our pains and tragedies will work for our good. (Rom. 8:28)
Now if we really have all this satisfaction and joy and enthusiasm in God, our most natural outward response should be happiness and gladness. That is because our "happenstance" happens to be in Christ.
"Happy are you, O Israel! Who is like you, a people saved by the Lord, the shield of your help, and the sword of your triumph! Your enemies shall come fawning to you, and you shall tread upon their backs.” - Deut 33:29
How beautiful upon the mountains are the feet of him who brings good news, who publishes peace, who brings good news of happiness, who publishes salvation, who says to Zion, “Your God reigns.” - Is. 52:7
If we do not have this happiness/ gladness at all in our relationship with the Lord, it is a question if we really do know the Lord. We should pursue our own happiness in God and fight to keep it. We are commanded many times in the Bible to be happy/ glad in God:
1 Chronicles 16:31 (Show me 1 Chronicles 16)
Let the heavens be glad, and let the earth rejoice, and let them say among the nations, “The Lord reigns!”
Phil. 4:4 - Rejoice in the Lord always, and again I say, "rejoice"!
1 Thess. 5:16-18 - "Rejoice always, 17 pray without ceasing, 18 give thanks in all circumstances; for this is the will of God in Christ Jesus for you.
We are even threatened if we will not be happy in God:
47 "Because you did not serve the Lord your God with joyfulness and gladness of heart, because of the abundance of all things, 48 therefore you shall serve your enemies whom the Lord will send against you, in hunger and thirst, in nakedness, and lacking everything. And he will put a yoke of iron on your neck until he has destroyed you." - Deut. 28:47-48
It is clear that we are to enjoy God because this is precisely the thing that glorifies Him. Loving God but not enjoying Him is an oxymoron. We love/enjoy God and through this we glorify Him before all the world.
So, my conclusion is, if we speak clearly and Biblically, we should urge people to pursue their highest satisfaction and joy and happiness - in Christ. That is the only place abiding happiness will be found.