War (U2 album) in the context of "Sunday Bloody Sunday"

U2 are an Irish rock band formed in Dublin in 1976. The group comprises Bono (lead vocals), the Edge (lead guitar, keyboards, and vocals), Adam Clayton (bass guitar), and Larry Mullen Jr. (drums and percussion). Initially rooted in post-punk, U2's musical style has evolved throughout their career, yet has maintained an anthemic quality built on Bono's expressive vocals and the Edge's chiming, effects-based guitar sounds. Bono's lyrics, often embellished with spiritual imagery, focus on personal and sociopolitical themes. Popular for their live performances, the group have staged several elaborate tours over their career.

The band was formed when the members were teenaged pupils of Mount Temple Comprehensive School and had limited musical proficiency. Within four years, they signed with Island Records and released their debut album, Boy (1980). Works such as their first UK number-one album, War (1983), and singles "Sunday Bloody Sunday" and "Pride (In the Name of Love)" helped establish U2's reputation as a politically and socially conscious group. Their fourth album, The Unforgettable Fire (1984), was their first collaboration with producers Brian Eno and Daniel Lanois, whose influence resulted in a more abstract, ambient sound for the band. By the mid-1980s, U2 had become renowned globally for their live act, highlighted by their performance at Live Aid in 1985. Their fifth album, The Joshua Tree (1987), made them international stars and was their greatest critical and commercial success. One of the world's best-selling albums with 25 million copies sold, it yielded the group's only number-one singles in the US: "With or Without You" and "I Still Haven't Found What I'm Looking For".

Psalm 40 is the 40th psalm of the Book of Psalms, beginning in English in the King James Version: "I waited patiently for the LORD". The Book of Psalms is part of the third section of the Hebrew Bible, and a book of the Christian Old Testament. In the slightly different numbering system used in the Greek Septuagint and Latin Vulgate translations of the Bible, this psalm is Psalm 39. In Latin, it is known by the incipit, "Expectans expectavi Dominum". It is described by the Jerusalem Bible as a "song of praise and prayer for help".

Psalm 40 is used in both Jewish and Christian liturgies. It has been set to music, Baroque settings and U2's song "40" from their 1983 album, War. Two composers used the beginning for symphonic compositions, Mendelssohn's Lobgesang and Stravinsky's Symphony of Psalms.

The Unforgettable Fire is the fourth studio album by Irish rock band U2. It was produced by Brian Eno and Daniel Lanois, and released on 1 October 1984 by Island Records. The band wanted to pursue a new musical direction following the harder-hitting rock of their previous album, War (1983). As a result, they employed Eno and Lanois to produce and assist in their experimentation with a more ambient sound. The resulting change in direction was at the time the band's most dramatic. The album's title is a reference to "The Unforgettable Fire", an art exhibit about the atomic bombing of Hiroshima.

Recording began in May 1984 at Slane Castle, where the band lived, wrote, and recorded to find new inspiration. The album was completed in August 1984 at Windmill Lane Studios. It features atmospheric sounds and lyrics that lead vocalist Bono describes as "sketches". "Pride (In the Name of Love)" and "MLK" are lyrical tributes to Martin Luther King Jr.