Adam Clarke on Acts 25:19

Questions - of their own superstition - Περι της ιδιας δειδιδαιμονιας; Questions concerning their own religion. Superstition meant something as bad among the Romans as it does among us; and is it likely that Festus, only a procurator, should thus speak to Agrippa, a King, concerning his own religion? He could not have done so without offering the highest insult. The word δεισιδαιμονια must therefore simply mean religion - the national creed, and the national worship, as I have at large proved it to mean, in the observations at the end of Act 17:34.

And of one Jesus, which was dead, etc. - In this way does this poor heathen speak of the death and resurrection of Christ! There are many who profess Christianity that do not appear to be much farther enlightened.