The great Al Jarreau created many jazzy and soulful records, but the most soulful records of his career were two albums released on Tax Scam label Koala in the late seventies. "Call me" is an LP of Al Green covers where Al Jarreau sounds very Al Green-ish throughout. The "Lonely Town. Lonely Street" LP is an album of Bill Withers covers, also excellent and this one was released in at least three different versions in the late seventies.
"Call me" is by far the rarer of the two but both albums are well worth seeking out.