What is the significance of the title, Wheat That Springeth Green?

The novel’s title comes from a fifteenth century French Easter carol (later adapted as the familiar carol “Sing We Now of Christmas) called "Now the Green Blade Riseth." It lyrics, which speak of the earth's return to life in the spring, symbolizes the spiritual redemption of Joe Hackett. The hymn, most often part of contemporary funeral rites, sings of how in the late spring the winter wheat, long thought dormant, comes back to glorious verdant life. The lyrics, once stirring and inspirational, represent Joe’s own midlife return to the spiritual intensities and prayerful rewards that first attracted him to a life in the Church. Joe, dead spiritually, finds in his new work in the slums of Minneapolis that he is restored, spiritually resurrected. As the hymn proclaims: “Now the green blade riseth/ from the buried grain/ Wheat that in dark earth many days has lain/Love lives again, that with the dead has been/Love is come again like wheat that springeth green.”