Martin Luther encouraged praying the Psalms by providing the common people with singable versions of metrical psalms in their own language.
He acknowledged that,
the common and ancient custom of the Christian church [was] to sing Psalms. St. Paul himself instituted this in I Corinthians 14:15 and exhorted the Colossians [3:16] to sing spiritual songs and Psalms heartily unto the Lord so that God’s Word and Christian teaching might be instilled and implanted in many ways.
(Hughes Oliphant Old, Worship: Reformed According to the Scriptures, (Atlanta, Georgia: John Knox Press, 1984), 48.)
As early as 1537 the Strasbourg Psalter included vernacular versions of all one hundred and fifty psalms.” Luther turned six Psalms into evangelical song (12, 14, 67, 124, 128, 130, and then later Psalm 46).
Hughes Oliphant Old claims that “Martin Luther did as much as anyone to revive and popularize psalm singing in the sixteenth century.”