Chapter sixteen concludes this discourse with final encouragements for the apostles. Jesus said that he specifically told them these things, rather than just letting them happen, “so that you will not fall away” (John 16:1). No matter what situation they faced, they would have the indwelling Holy Spirit and the promise of the coming Savior himself. The Holy Spirit would go into the world before them, convicting people before the apostles preached the gospel. In this sense, it was actually better than even having Jesus with them (John 16:5-11).
Jesus also promised that the Holy Spirit would continue to teach them, since he would be speaking from God as did Jesus (John 16:12-16). There were things they just would not have been able to understand yet at that point.
Throughout this discourse they had many questions. John did not record most of them in the previous chapters, but now that Jesus had approached the end, he acknowledged their questions and promised that they would understand everything in time (John 16:19-33).
One final change between their old way and the new way to come was the method of prayer (John 16:24-28). Jesus said that to that point they had not prayed in his name, but this was about to change. Now we pray to the Father in the name of (or with the authority and privilege of) Jesus himself. One last time he warned them of the trouble they were to face, but that they should not worry because he had already conquered the world.