Jesus has been preparing his disciples for his death but notice that in John the betrayal by Judas occurs in chapter 13 (out of 21) whereas in Mark in 14 (of 16), Luke in 22 (of 24), Matthew 26 (of 28). The synoptic gospels spend the bulk of their time telling us about Jesus’ life and spend less time on his betrayal, death, and resurrection. John is a long gospel and thus the amount of material concerning this later time is considerable. What was John’s point in this? Why does he not include most of the synoptic material of what Jesus did during his years of ministry? John is usually dated much later than the synoptic gospels and thus there probably was no reason for him to repeat information that was already widely available in those accounts.
John now provides a lot of information that is crucial for Christians living during this tumultuous period and after Jesus ascended to heaven. Jesus comforted the disciples, explaining what he was doing (going to prepare a place for them) and his relationship to the Father. He also promised that the Father will send them an advocate (Holy Spirit) if they love Jesus and keep his commands. Although the world will hate them this Advocate will testify about Jesus “and you also must testify, for you have been with me from the beginning” (15:27). Many Christians did testify and were martyred because of it.