My daughters' Friends School sang this song after morning meeting today -- it was so lovely and perfect for this season, I was compelled to find out more. A few renditions are on the YouTube sidebar.
(A bit of a detailed history and analysis can be found at the American Music Preservation site)
Lyrics and music by Elder Joseph Brackett at the Shaker community in Alfred, Maine, 1848.
Aaron Copeland included it in his Appalachian Spring symphony in 1955.
Tis the gift to be simple, 'tis the gift to be free,
'Tis the gift to come down where we ought to be,
And when we find ourselves in the place just right,
'Twill be in the valley of love and delight.
When true simplicity is gain'd
To bow and to bend we shan't be asham'd,
To turn, turn will be out delight
'Till by turning, turning we come round right.