This Psalm looks like a simple song, perhaps one that was taught to children to help them think about what God did for Israel in the Exodus, when he parted the Red Sea so Israel could cross over on dry land. God did this so that he could have a people who remembered his deeds, and they would keep themselves holy so he could dwell among them (1-2). God will also dwell with us if we remember his saving work in Jesus and give him praise.
Imagine if we saw the sea turn and flee, the mountains leap away, and a spring of water coming from a rock. How would we feel? We would ask, "Who could do this?" (3-6) Then we would realize the power of God and tremble. According to the Psalmist, it was the very majesty of God's presence that caused the seas to shrink back. It is good for us to tremble sometimes at the sense of God's presence. We should pray for everyone on earth to tremble at the power of God (7).
Application: Lord, help me be awed and tremble at the majesty of your presence, so I can have a right heart. May you dwell in my heart when I remember your salvation in Jesus.
One Word: Tremble at the presence of the Lord.