Good Book vs sacred writing

Good Book and sacred writing both are nouns.

Word	Noun	Adjective	Verb	Adverb
Good Book	Yes	No	No	No
sacred writing	Yes	No	No	No

As nouns, sacred writing is a hypernym of Good Book; that is, sacred writing is a word with a broader meaning than Good Book:

Other hypernyms of Good Book include religious text, religious writing, sacred text.

Good Book (noun)	sacred writing (noun)
the sacred writings of the Christian religions	writing that is venerated for the worship of a deity