This verse might be a bit unsettling to you. It thunders the majesty and power of God. It is entirely proper for us to be awestruck and fearfully reverent like the Israelites were with the cracks of lightning, shaking mountain, and blasting trumpet sounds at Mount Sinai (see Exodus 20:18.) Jesus is our Friend and Brother, but we also must remember that He is the sovereign God, the Great King before whom all heaven and earth will one day bow.
There are essentially two reactions we can have to this truth. One is to rebel against His authority the same way the kings of the earth through the centuries have tried in vain to do (see Psalm 2). The other is to surrender according to the terms of peace He offers, falling in behind Him as one of the happily conquered.
And when the Lord allows hardships into our lives, this verse along with many others reminds us that while He does whatever He pleases, He is good. When the mountains of life tremble before us, we know that our all-powerful King changes everything.