The Middle

Praise the Lord, all you nations! Extol him, all you peoples! For great is his steadfast love toward us, and the faithfulness of the Lord endures forever. Praise the Lord!
Ps. 117 

There are 1189 chapters in the scriptures and Psalm 117 is the 595th, making it the middle chapter of the entire Bible—an odd distinction for what is also the shortest chapter of the Bible, with just two verses. But what Psalm 117 lacks in length it makes up for in grandeur. In its straightforward praise, it is, indeed, worthy of study and repetition. One of the best ways to remember it is through a metrical version of it:
All who on earth do live,
to God all glory give:

Praise ye the Lord!
His loving-kindness bless,
his constant faithfulness

and changeless truth confess:
Praise ye the Lord!
Lord God, you have revealed your kindness to all peoples. Gather all nations to yourself, that in all the various tongues of the earth one hymn of praise may rise to you; through Jesus Christ, who taught us to pray: Our Father...
 Lutheran Book of Worship (ELCA) 

Since I'm including an Advent or Christmas song every day in December, I think this one best represents Psalm 117. It's a canticle called The First Song of Isaiah (from Isaiah 12), the translation is from the Episcopal Book of Common Prayer, and the composer is Jack Noble White.