"Serenity," the sixth song Ives' (loose) song set Seven Songs for Voice and Piano, was actually published in 1930. The composition date is listed as 1919 in Ives's song collection 114 Songs, in which "Serenity" is the 42nd song.
The song "Serenity" has the subtitle "A unison chant," and Ives remarks that the song is to be sung "Very slowly, quietly and sustained, with little or no change in tempo or volume throughout."
O, Sabbath Rest of Galilee!
[Excerpt from the poem "The Brewing of Soma"]
by John Greenleaf Whittier
O, Sabbath rest of Galilee!
O, calm of hills above,
Where Jesus knelt to share with Thee,
the silence of eternity
Interpreted by love.
Drop Thy still dews of quietness,
till all our strivings cease:
Take from our souls the strain and stress,
and let our ordered lives confess,
the beauty of thy peace.