For your wedding song, I submit “As Long as the Grass Shall Grow” by Johnny and June. This version is from the Unearthed box set, and was recorded around the time of Cash’s second album with Rick Rubin, Unchained.
The song was originally written by American Indian folk singer Peter La Farge, lamenting the Seneca Indians’ forced relocation to facilitate the building of the Kinzua Dam in Pennsylvania in the early 1960s. Johnny Cash covered this version of the song on Bitter Tears, a 1964 concept album about the plight of the American Indian. (You can hear that version here.) (La Farge also wrote another, much more famous Johnny Cash song, “The Ballad of Ira Hayes,” also on Bitter Tears.)
Folk music has a long tradition of re-using melodies. Woody Guthrie’s most famous song, “This Land is Your Land,” was originally the Carter Family’s Book of Revelation (I think) epic “When the World’s on Fire” (which I will post on at some point in the future), just as his song with the Almanac Singers, “The Sinking of the Reuben James” borrowed heavily from the Carter Family’s “Wildwood Flower.”
When he re-recorded “As Long as the Grass Shall Grow” much later in life, Cash kept the chorus and rewrote the verses, turning a powerful and bitter protest song into a gorgeous and equally powerful love song about meeting and loving June Carter, who sings on the chorus. It’s clear that both of them meant every word.
I don’t know how good it is for dancing and the lyrics may be too specific for your purpose, but I always thought it would make a lovely wedding song. I’m happy to share it with you and our readers.
Congratulations to both of you!