Psalm 42 in the context of "Book of Psalms"

A liturgical book, or service book, is a book published by the authority of a church body that contains the text and directions for the liturgy of its official religious services.

Psalm 83 is the 83rd psalm of the Book of Psalms, beginning in English in the King James Version: "Keep not thou silence, O God". In the slightly different numbering system used in the Greek Septuagint and Latin Vulgate translations of the Bible, this psalm is Psalm 82. In Latin, it is known as "Deus quis similis erit tibi ne taceas". It is one of the 12 Psalms of Asaph. This psalm is the last of the Psalms of Asaph, which include Psalms 50 and 73 to 83. It is also the last of the "Elohist" collection, Psalms 42–83, in which the one of God's titles, Elohim, is mainly used. It is generally seen as a national lament provoked by the threat of an invasion of Israel by its neighbors.

The psalm forms a regular part of Jewish, Catholic, Lutheran, Anglican and other Protestant liturgies. It has been set to music, including works by Heinrich Schütz and Alexander von Zemlinsky.