The answer is: Psalm 117

Psalms 117:1-2 - This psalm is remarkable not only for its brevity but also for its universal call to praise. It emphasizes God’s steadfast love and faithfulness, a theme echoed throughout the Bible. Interestingly, it's the middle chapter of the entire Bible, bridging both Testaments in its declaration of worship.

Psalm 117, with just two verses, serves up an astonishing mix of powerful praise and an invitation for all nations to join in. Did you know it’s not only short but also the very center of the Bible? Nestled neatly between the hefty historical accounts of the Old Testament and the new teachings found in the New Testament, it stands as a heartwarming reminder of our shared humanity and the divine love that permeates all of scripture.

Encouraging all nations to praise God, it shows us that love isn’t confined; it flows beyond borders and cultures. Paul, in his letters, often echoed sentiments like this, highlighting the idea that faith is for everyone, not just a select few. That sense of inclusivity in Psalm 117 can also make us reflect on communities today and how we can also cultivate spaces where all voices are welcomed and honored.

Moreover, this Psalm is quoted in the New Testament, reaffirming its timeless relevance. It resonates with sections in Debarim (Deuteronomy) as well, reminding readers that there’s a powerful thread of continuity connecting various messages and themes across the texts.

So when you find yourself humming along with the simple yet profound words of Psalm 117, remember, you’re engaging in a joyous expression that ties together people from all corners of the world under the banner of love and faithfulness. The universality of this call remains as potent today as it was thousands of years ago.