Definition of "Gospel" :

noun: a doctrine that is believed to be of great importance

"Newton's writings were gospel for those who followed."

noun: the four books in the New Testament (Matthew, Mark, Luke, and John) that tell the story of Christ's life and teachings

noun: an unquestionable truth

"His word was gospel."

noun: the written body of teachings of a religious group that are generally accepted by that group

noun: folk music consisting of a genre of a cappella music originating with Black slaves in the United States and featuring call and response; influential on the development of other genres of popular music (especially soul)