The brethren — That is, the Christians. Our Lord himself taught them that appellation, John 20:17. Yet Jesus did not say to him, that he should not die — Not expressly. And St. John himself, at the time of writing his Gospel, seems not to have known clearly, whether he should die or not.
Related Commentaries of John 21:23
John 21:23
23 Then went this saying abroad among the brethren, that that disciple should not die: yet Jesus said not unto him, He shall not die; but,If I will that he tarry till I come, what is that to thee?