The verb, ἐντρίβομαι, appears to be used by St. Basil, if he wrote ἐντετριμμένων in the sense of to be ἐντριβής or versed in a thing (cf. Soph. Ant. 177)—a sense not illustrated by classical usage.  But the reading of the Moscow ms. (μ) ἐντεθραμμένων, “trained in,” “nurtured in,” is per se much more probable.  The idea of the country folk preserving the good old traditions shews the change of circumstances in St. Basil’s day from those of the 2d c., when the “pagani” or villagers were mostly still heathen, and the last to adopt the novelty of Christianity.  cf. Pliny’s Letter to Trajan (Ep. 96), “neque civitates tantum sed vicos etiam atque agros superstitionis istius contagio pervagata est.”