Withers wrote this and released it as a single from his album Still Bill in April 1972. It reached No 1 in America and No 18 in Britain. I have to say I don’t think he is the most tuneful singer of all time.
Here is a live performance.
Bill Withers: Lean on Me
Square
A few years later he did “Lovely Day”, one of the best songs of the 1970s.