John Calvin on Ephesians 3:2

2. If ye have heard. There is reason to believe, that, while Paul was at Ephesus, he had said nothing on these subjects, no necessity for doing so having arisen; for no controversy had taken place among them about the calling of the Gentiles. If he had made any mention of them in his discourses, he would have reminded the Ephesians of his former statements, instead of referring generally, as he now does, to common report and to his own Epistle. He did not, of his own accord, raise unnecessary disputes. It was only when the wickedness of his adversaries made it necessary, that he reluctantly undertook the defense of his ministry. Dispensation (οικονομια) means here a divine order or command, or, as it is generally expressed, a commission