10 For there are many rebellious people, mere talkers and deceivers, especially those of the circumcision group. 11 They must be silenced, because they are ruining whole households by teaching things they ought not to teach—and that for the sake of dishonest gain. 12 Even one of their own prophets has said, “Cretans are always liars, evil brutes, lazy gluttons.” 13 This testimony is true. Therefore, rebuke them sharply, so that they will be sound in the faith 14 and will pay no attention to Jewish myths or to the commands of those who reject the truth.
'Kay, Paul, tell us how you really feel.
The nastygram here is myths. The Greek doesn't add much here, since it's a direct lift from the Greek mythos, which can either mean a story or a fiction depending on the context; you could say something like "The myth of Tim Tebow continue to build with a beefcake run in the rain" without insulting anyone. However, Paul was using the pejorative version, as nasty as a secularist starting a Bible story with "once upon a time..."
We don't divide on Jew-Gentile lines in the church these days, but we do divide on lines of Solo Fide versus folks who harken to James in saying that faith without some works is useless.
From a New Covenant perspective (speaking loosely) it's baptism that takes the place of circumcision as the ceremony that makes you part of the club. Baptism has the advantage of being co-ed and no where nearly as painful; traditional Judaism had a bit of a barrier to entry, as we'd say in microeconomics.