The New Testament writings of John are ingenious. He employed a very small palette of simple terms—almost Hop on Pop-simple—but he used them in a way that imbued each with a rich and subtle blend of meanings. Then he combined these simple terms so as to create profound and complex descriptions of ultimate reality and what it means to believe in Jesus. At the same time, his core messages remain simple, so simple that some of John's sayings are among the first parts of the Bible we teach our children to memorize.
A marvelous example is John 17. Jesus' disciples heard him pray many times, but this is the only prayer longer than a sentence or two that is recorded in the Gospels. It is the climax of Jesus' last, most intimate teaching to the twelve disciples (minus Judas Iscariot) before going to the cross, after which his contact with them would be intermittent. Jesus ends the discussion with a prayer that expresses the reason for everything he was doing and sketches the future of all who believe that he is who he says he is.
The Greek text of John 17 contains 505 words. These include only twenty-five different nouns. (Pronouns do a lot of the heavy lifting.) But with these nouns Jesus describes a dynamic that is easier depicted than retold.
The Father and the Son are in an eternal relationship of glory-giving. The Father glorifies the Son by giving him all of his authority. The Son glorifies the Father by giving him all of his obedience. This glory spiral has been going on in heaven forever but has more recently come to earth. As Jesus approaches the cross, the place of utmost shame to the world, the glory spiral accelerates.
The eleven remaining disciples were called out from the world—humanity generally, but more to the point the system(s) of human functioning in this age. They did not know it, but they always belonged to the Father. For that reason, the Son spoke to them about his one-of-a-kind position in the glory spiral, and the disciples believed it.
Jesus asks the Father to put the full magnitude and quality of the oneness, joy, and truth they share with one another into the disciples. These qualities, which are at the heart of the divine relationship of the glory spiral, are necessary to protect the disciples from the evil one. This is critical, because Jesus is sending them who have been called out of the world back into the world.
People are going to believe the disciples' message about the glory spiral of the Father and the Son. Jesus prays that the Father would make all believers every bit as one as the Father and the Son are one—which of course is complete, perfect, total, pure—by drawing them into the Godhead's own oneness. When believers manifest divine oneness, it will draw more people out of the world into the glory spiral.
That's what Jesus came for. That's what Jesus asked for. And someday he's going to get every bit of it.