Following the first reading in a Catholic wedding, the community sings or recites the Responsorial Psalm, taken from the book of Psalms in the Old Testament. Seven psalms have been chosen as particularly suitable for the celebration of weddings. The book of Psalms is an ancient book of 150 prayers written as song. Some of the psalms were written as early as 900 years before the birth of Jesus. The Church continues to use the psalms as a prayerful response to the Word of God proclaimed in the first reading. Generally responsorial psalms are structured so that there is a refrain sung by the whole congregation with verses led by a cantor.