“Sanctify them by the truth; your word is truth.”
John and Peter, of all the disciples had a special relationship with Jesus. Jesus even allowed them time to commune with Abraham and Moses. John writes in a particular style that is also evident in his letters and in Revelations. Earlier, John had written that Jesus was the Word made flesh. That flesh was sacrificed by God, as a gift to those whom God loved, so that God could abide them Because eternal life is close proximity to God. And to perish is to be utterly riven from God.
Here, at Gethsemane, Jesus is praying the night before he is to be crucified. At first Jesus prays for himself, then his disciples, then other believers.