Metrical psalter

A metrical psalter is a kind of Bible translation: a book containing a verse translation of all or part of the Book of Psalms in vernacular poetry, meant to be sung as hymns in a church. Some metrical psalters include melodies or harmonisations. The composition of metrical psalters was a large enterprise of the Protestant Reformation, especially in its Calvinist manifestation.

During the Protestant Reformation, a number of Bible texts were interpreted as requiring reforms in the music used in worship. The Psalms were particularly commended for singing. In particular, John Calvin said,

When we have looked thoroughly everywhere and searched high and low, we shall find no better songs nor more appropriate to the purpose than the Psalms of David which the Holy Spirit made and spoke through him

Various Reformers interpreted certain scriptural texts as imposing strictures on sacred music. The psalms, especially, were felt to be commended to be sung by these texts. One example is James 5:13 (KJV)

"Is any merry? let him sing psalms."

(The word translated "sing psalms" in the KJV at James 5:13 is ψαλλετω. Some other versions give more general translations such as "sing praise" in the ESV.)

Another key reference is Colossians 3:16

"Let the word of Christ dwell in you richly as you teach and admonish one another with all wisdom, and as you sing psalms, hymns and spiritual songs with gratitude in your hearts to God."