Rejoicing (or being happy?) always

I confess that I did have a small quibble with George Eliot on Happiness. The reason being that the very word "happy", and thus its meaning, derives from hap, happenstance, and so forth. In other words, what's happening. And thus I'm not convinced that you can completely divorce happiness from circumstances. If a person isn't rendered happy by some circumstances and sad by others, I'm not so sure they're healthy (or very empathetic).

But there is something that transcends circumstances, and I think it's a larger and deeper thing than happiness, as it stands by definition, though in alignment with Eliot's "complex of habitual relations and dispositions". I do think it's closer to joy (even the word "cheer" derives from "mental condition" which is perhaps closer the mark). I know John Piper is Mr Joy, but I have been reminded of a sermon called Rejoicing Always by John MacArthur. It's good, and what's brilliant is that you can actually read it, you don't have to listen to it. In it he makes a case for a difference between joy and happiness.