The living legends delve into their gospel roots and come up with a set that burns as brightly as the star of Bethlehem. With Sunday Down South, Lewis and Cash revisit the great standards, such as “Will the Circle Be Unbroken” and “Give Me That Old Time Religion,” as well as interpreting the New Orleans favorite “When the Saints Go Marching In.” While the songs are not all traditional gospel favorites, the blend of folksy Sunday-afternoon-drive music makes for a winning package.