All 3 Uses

gospel
in
The Autobiography of Miss Jane Pittman
(Edited)

"And that makes it gospel truth," he said.
Chpt 3 *

gospel = an unquestionable truth
We didn't like for him to listen to the radio, either; 'less he was listening to gospel music on Sundays.
Chpt 4 *

gospel = a type of vocal music that originated in African-American churches in the United States
Listening to his travels we knowed he was close to God, and now we wanted him to pick up the gospel.
Chpt 4 *

gospel = the religious teachings of Jesus

Definitions:

(1) (gospel as in: gospel of the Bible)
the religious teachings of Jesus

or:

one of the four books in the New Testament (Matthew, Mark, Luke, and John) that Christian's believe tell the story of Jesus Christ's life and teachings
(2) (gospel as in: they consider it gospel)
a set of beliefs firmly held by a group

or:

an unquestionable truth
(3) (gospel as in: gospel music)
a type of vocal music that originated in African-American churches in the United States
(4) (meaning too rare to warrant focus)