She's always spreading/preaching the 'gospel' of good health. [=telling people about the importance of good health]
I didn't do it, and that's 'the gospel truth'. [=the absolute truth; a completely true statement]
These myths are 'accepted/taken as gospel' [=believed to be true] by many teenagers.
(..) it's the sort of thing that Miggs would say. Not any more. Thank you, Barney. What happened to your drawings? Punishment, you see, for Miggs. Just like that gospel program. When you leave, they'll turn the volume way up. Dr Chilton does enjoy his petty torments. What did you mean (..)1991 The Silence of the Lambs