Joseph Benson's Commentary of the Old and New Testaments - John 21:24
John 21:24. This is the disciple which testifieth these things Being still alive after he had written them. From this verse Grotius and some others infer, that the Ephesian bishops added this whole chapter to St. John’s gospel, after his death. But, as Dr. Macknight observes, it evidently proves the contrary, for it assures us that John wrote the things contained in this chapter. And we know that his testimony is true The church probably added these words to this gospel, as Tertius did... read more
Albert Barnes' Notes on the Whole Bible - John 21:24
This is the disciple ... - This proves that the beloved disciple was John.We know - That is, it is known; it is universally admitted. It was so decidedly his character that he always declared the truth, that it had become known and was unquestioned, so that he himself might appeal to the universal testimony in his behalf. In this case, therefore, we have the testimony of a man whose character for nearly a century was that of a man of truth - so much so that it had become, in a manner,... read more