Note 12 at Eph. 4:21: The phrase "If so be" is what is called "a conditional clause." It is not expressing doubt that these Ephesians had heard the Lord speak to them and teach them. It's just the opposite. The statement could be paraphrased, "You did hear (Jesus), didn't you?" You were taught by Him weren't you? The truth is in Jesus, and if that be so you know there is no room for the conduct or behavior of the world (see note 3 at v. 17, p. 1121) in the Christian life!