Psalms 117:1-2
1 O praise the LORD, all ye nations: praise him, all ye people.
2 For his merciful kindness is great toward us: and the truth of the LORD endureth for ever. Praise ye the LORD.
This is the shortest Psalm. All the earth, all the nations, are now called upon to praise, because His merciful kindness has been great towards His people Israel. And their blessing means the blessing of the world. See the significant and interesting verse in Deuteronomy 32:43, the last note of Moses' prophetic song. Hallelujah.