The Statler Brothers

The Statler Brothers (sometimes simply referred to The Statlers) were an American country music, gospel, and vocal group. The quartet was formed in 1955 performing locally and, in 1964, they began singing backup for Johnny Cash until 1972.
Don Reid sang lead; Harold Reid, Don's older brother, sang bass; Phil Balsley sang baritone; and Lew DeWitt sang tenor and was the guitarist of the Statlers before being replaced by Jimmy Fortune in 1983 due to DeWitt's ill health. 
DeWitt continued to perform as a solo artist until his death on August 15, 1990, from heart and kidney disease. On April 24, 2020, Harold Reid died of kidney failure.