John 21 - NIV Essentials Study Bible

21:4 did not realize that it was Jesus. Cf. Mary Magdalene (see note on 20:14).

21:18 stretch out your hands. The early church understood this as a prophecy of crucifixion.

21:19 the kind of death. Peter would be a martyr. Tradition indicates that he was crucified upside down.

21:25 even the whole world would not have room. Hyperbole (for another example of this figure of speech, see Lk 14:26 and note). Our historical knowledge of Jesus is at best partial, but we have been given all we need to know.