John 17 is a chapter in the Bible where Jesus is talking to God (his Father). He is saying goodbye to his friends, the disciples, and is getting ready to leave them. In this chapter, Jesus is asking God to take care of his friends and to help them remember his teachings.
Jesus also talks a lot about how he and God are one. He says that he came to Earth to do what God sent him to do, and now he is finished with that job. He also prays that his followers will always believe in him and stay true to his teachings.
So basically, John 17 is a conversation between Jesus and God where Jesus is asking God to take care of his friends and help them remember his teachings. He also talks about how he and God are one, and that he came to Earth to do God's work.