John 21:14
This is now the third time that Jesus shewed himself to his disciples, after that he was risen from the dead.
Cross-reference
John 20:19
Historical context
In John 20:19, Jesus first appears to the disciples in the upper room — John 21:14 notes this as the third appearance, connecting the sequence.
John 20:26
Citation
In John 20:26, Jesus appears again (to Thomas) — John 21:14 counts this as the third appearance, tying the resurrection accounts together.