“This is the Disciple which testifieth of these things, and wrote these things, and we know that his testimonie is true.”
1611 King James Version (KJV)
21:24 This is the disciple who testifieth - Being still alive after he had wrote. And we know that his testimony is true - The Church added these words to St. John's, Gospel, as Tertius did those to St. Paul's Epistle to the Romans, #Rom 16:22|.
Joh 21:24 We know that his testimony is true. Many suppose the last two verses were added by another hand than John's, perhaps by the elders of the church at Ephesus, where John wrote, who give their endorsement to his record.