David makes it clear that he cannot be moved because God is His only rock, God is his only salvation and God is his only defense.
This is very important because we tend to lean on other rocks in our lives, at least I do!
What are your other rocks?
I've had many false rocks over the years only to watch them disinegrate before my eyes.
- other people
- my own false notion of control
- the list could just go on
God loves us and He is jealous. He is faithful to remind us that we only need one rock and that's Him. People can come and go but if I lean on Him I'm not moving.