One of the Cretans, a prophet of their own, said, “Cretans are always liars, evil beasts, lazy gluttons.”
Titus 1:12

Per John Gill, numerous ancient poets agreed in characterizing Cretians as given to dishonesty and violence. In this verse, Paul quoted the poet Epimenides on this score. There are numerous quotes in the Bible of extra-biblical literary sources, and none of those quotes mean that the original source should be included in the Bible.