NET

19 They went out from us, but they did not really belong to us, because if they had belonged to us, they would have remained with us. But they went out from us to demonstrate that all of them do not belong to us.

Darby

19 They went out from among us, but they were not of us; for if they had been of us, they would have surely remained with us, but that they might be made manifest that none are of us.

KJV

19 They went out from us, but they were not of us; for if they had been of us, they would [no doubt] have continued with us: but [they went out], that they might be made manifest that they were not all of us.