The Purpose Driven Life devotional was really good this morning. It talked about how Ps 51:12 can sometimes get mis-quoted as "restore unto me the joy of my salvation" instead of "Thy salvation."
One little word can make a big difference: "my salvation" implies that it originated with me; "Thy salvation" acknowledges that it is not mine, it is a gift from God.
The devotional goes on to say:
"If our joy about Jesus is based on what we’ve done, then we’ll always wonder if we’ve done enough. That joy is only temporary. But if our Jesus-joy is based on the grace of God, it’s permanent – “it is finished.” (John 19:30)"
That's true... but in my experience I'd have to take it a step further. I don't think there's any real joy in the "my salvation" view. There's a lot of fear and worry, punctuated by short periods of relief that might appear to be joy... but it's just a deceptive calm.