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.
". . . a person who makes a genuine confession can be expected to persevere in his faith, although elsewhere John warns his readers against the danger of failure to persevere [cf. 1 John 2:24; 2 John 1:8]." [Note: Marshall, p. 152.] 