Psalm 117:1-2 (KJV) 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. 

It is the LORD’s merciful kindness that we are not consumed but have life. For He gives and sustains all lives, even the nations. It is therefore most important that the nations having enjoyed the goodness of the LORD give thanks to Him.

Out of the nations, He has called His people. Praise therefore is comely.

And thus, the psalmist exhorts the nations to acknowledge the merciful kindness of the LORD. Amen.