The words "happy" and "happiness" come from the root HAP, which signifies "chance." If a combina-tion of things line up to produce something that is pleasant, you are happy. But when those things fall out of alignment, according to the vagaries of the flow of daily events, happiness disappears and you are left flat, empty, and let down. Such alignment of the components of happiness is a chance occur-rence, and thus happiness is the product of chance. Daily life is a succession of such a rise and fall in chance. But joy, as a gift of God, is not by chance. It is an act of God. And it stays with you, unchanged, unless you choose to hand it back to God through sin and foolishness.
If further proof is needed that joy is a gift of God, then consider Gal. 4:22, where it lists the "fruits of the Spirit." Of the nine things named, the second is joy! The expression "fruits of the Spirit" means "precious results that the Holy Spirit produces in our life." And such is JOY! It is indubitably a gift of God. Nowhere in Scripture does it say "happiness" is a "fruit of the Spirit" or a gift of God. That is because, as I have just shown, happiness is the product of chance.
In the past, when I have spoken on this subject, I have heard the comment that it is "just a matter of word meanings." That dismisses all the testimony and proof presented. And that, my friends, is sheer foolishness and the product of mental laziness. Words express units of thought; it's the main way we communicate ideas. And we can accurately communicate ideas only with words that have accurate meaning. When we are talking about the things of God and His revelation, we absolutely MUST use words that express in truth the meaning involved. I take word meaning seriously, and I try very hard to use language that is faithful to the meaning intended. Extemporaneous speaking, while appealing to most listeners, very often fails in using words accurately.