There are 150 poems called "Psalms" in the Old Testament, which are divided into five parts, including hymns to praise God or pray for God's blessing. Most of them were sung by Jews in the cathedral.
Many hymns were written by King David, a Jewish king. He was also a musician, and some were written by Korah's son and Moses.
The 23rd hymn, "The LORD is my shepherd, and I will never want …", is perhaps the most well-known poem.