Gospel vs sacred text

Gospel and sacred text both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gospel	Yes	No	No	No
sacred text	Yes	No	No	No

As nouns, sacred text is a hypernym of Gospel; that is, sacred text is a word with a broader meaning than Gospel:

Gospel: the four books in the New Testament (Matthew, Mark, Luke, and John) that tell the story of Christ's life and teachings
sacred text: writing that is venerated for the worship of a deity

Other hypernyms of Gospel include religious text, religious writing, sacred writing.

Gospel (noun)	sacred text (noun)
the four books in the New Testament (Matthew, Mark, Luke, and John) that tell the story of Christ's life and teachings	writing that is venerated for the worship of a deity