Say or do

Rather than sending this phrase to my Portuguese-language twitter account, I accidentally sent it to my personal English account. This latter account is also posted automatically on Facebook, where it generated a bit of discussion, more on the point of languages than the content, but perhaps the Kingdom was served by all that.

There are people who say they’re concerned about sound doctrine, but support false teachers and spread their works. Should we believe what such people say or what they do?

The question is rhetorical.