Let the nations be glad and sing for joy, for you judge the peoples with equity and guide the nations upon earth. - Psalm 67:4
So for all you armchair Bible interpreters who want a neat way to hack the Psalms, I give up a simple little tip for unearthing the main point of almost every psalm. Just look at the middle. I know, mind-blowing right? It's a secret that's out in the open, a little too obvious to be true. Old Testament Hebrew constantly uses literary sandwiches with an A, B, C, B, A type pattern (what nerds call chiasms). If you think about A being the bread, B being your condiments, lettuce, tomatoes, then C is the meat, the main reason why you're biting into the sandwich in the first place. You need A and B to add a little pep, texture, flavor but what really feeds you, what sticks to the ribs, is going to be C. This typically ends up being the thesis of any Old Testament passage and regularly works for the psalms.
So a quick application of this to Psalm 67. Look at the first and last verse; a call for God to bless His people. Go a verse in from the ends, v.2 and 6. They speak of the earth as a whole responding to God. Take a quick pause and note how v.6-7 are a form of response to the call in v.1-2. The people pray that God would make His face shine on the people and that the earth would know His ways in v.1-2 and in v.6-7, the earth has received God's blessing and the earth is called to respond in kind.
Now move into v.3 and v.5. They're exactly the same, calling upon the people to praise the Lord. It's like walking between the two pillars that form a gateway to glory, as if they're guarding and protecting the treasure of truth that lies in between them. That would be v.4; "Let the nations be glad and sing for joy, for you judge the peoples with equity and guide the nations upon the earth." It's an exclamation of God's desire for this whole world, that any and all would come to sing His praises. That the world would be witness of God's greatness and respond in kind. It's a pre-Revelation picture of the new heavens and new earth. It's glorious, awe-inspiring, and worth rejoicing over. In a time where we're concerned about civil authorities both near and abroad, where it doesn't seem like this world can get along, we are reminded who is truly in control and how all things are in His hand. His faithfulness, sovereignty, and righteousness cannot be impugned upon by any earthly power. Instead, God's people have a place to give thanks and reason to call the nations to do the same.
The beauty of all this is how the structure of the poem builds up to v.4. Our appreciation of the psalms should go beyond picking out one pithy verse that brings us comfort or gives us fuzzy feelings. But a little simple interpretive legwork can sometimes bring out even greater delight in the book of God's songs and prayers.