1 God is our refuge and strength,
an ever-present help in trouble.
2 Therefore we will not fear, though the earth give way
and the mountains fall into the heart of the sea,
3 though its waters roar and foam
and the mountains quake with their surging.
Are you kidding us? You actually expect us to believe you are so serene in God that a cataclysmic earthquake could throw a mountain into the sea, and it wouldn't disturb you? "Oh, that's interesting. How different the mountain looks hurtling through the air. Wow, that splash looks cool. I wonder how big the tsunami is going to be. I'm glad I know God though, otherwise I'd worry."
I don't know about you, but I don't think I could pull that off. If I were at all calm as I watched a mountain flying overhead and splashing into the sea, it would be because I just couldn't believe what I was seeing. Could God keep me calm? I suppose possibly, if Jesus appeared to me, said "Steve, take my hand and close your eyes, you won't want to watch this next part".
But yet the statement isn't false. If I really understood who God is, and that he has promised to always be with me, and to work out every circumstance for good, I wouldn't panic at a huge earthquake altering the landscape or an asteroid the size of Russia heading right for me. I certainly wouldn't panic at some comparatively minor thing like a hurricane that merely flattened my house and cut off power and water to the neighborhood for a couple of weeks. And really minor things like a car wreck or losing my job or discovering I had cancer I'd barely notice.
I can expound how Scripture should give me that kind of confidence in God. But I don't have it. Maybe the Psalmist who wrote these words didn't have it yet either, maybe he wrote this to say "If I really believed what I know I should, I'd be calm." Maybe like me he wrote that down, looked at his words and prayed, "Lord I believe, yet help my unbelief. Help me really get this deep down."