40 (song)
"40", also known as "40 (How Long)", is the tenth and final track from U2's 1983 album, War. The song is noted for its live performances, often involving the audience singing along for minutes after the band has left the stage. The lyrics are a modification of the Bible's Psalm 40.
The song was released as a commercial single only in Germany, simply to promote U2's appearance at the Loreley Festival in 1983. The single was released on a 7" gramophone record with a B-side of the album version of "Two Hearts Beat as One". Since its live debut on February 26, 1983, in Dundee, "40" has been a staple of U2's live concerts, having been performed almost 400 times.
Recording
The song was recorded right at the end of the recording sessions for War. Bassist Adam Clayton had already left the studio, and the three remaining band members decided they didn't have a good song to end the album.Bono, The Edge, and Larry Mullen, Jr. quickly recorded the song with The Edge switching off to both the electric and bass guitar. Bono called the song "40" as he based the lyrics on Psalm 40.