The church in Ephesus weighed what the self-proclaimed apostles said (and perhaps their lifestyle) and concluded that they were not divinely sent; they found them to be false,
their teaching (and manner of living) to be inconsistent with the truth they had learned from the Old Testament as fulfilled in Jesus Christ and taught by the (true) apostles. The implication is that the saints of Ephesus had mastered God’s revelation as they received it over the years so that they were competent to weigh the words of these teachers.
2 “‘I know your works, your toil and your patient endurance, and how you cannot bear with those who are evil, but have tested those who call themselves apostles and are not, and found them to be false.