They went out from us, but they didn't belong to us; for if they had belonged to us, they would have continued with us. But they left, that they might be revealed that none of them belong to us.

 (i) It may mean, as in our translation: "All of them are not of us," or, as we might better put it, "None of them are from us." That is to say, however attractive some of them may be and however fine their teaching sounds, they are all alike alien to the Church. 