Charles Ellicott Commentary John 21:2

"There was together Simon Peter, and Thomas called Didymus, and Nathanael of Cana in Galilee, and the [sons] of Zebedee, and two other of his disciples." — John 21:2 (ASV)

The mistake having been made, the obvious correction after St. John’s death would have been simply to record that event. The correction of the text would place these words within his lifetime.