The High Priestly prayer of Jesus Christ is directed to God the Father from God the Son into which readers 'intrude'. In doing so, they stand on holy ground, and because of this, John 17 is one of the most wonderful and exciting portions in the whole of Scripture. It is spiritually profound and reaches depths we cannot plumb and heights we will never scale.
It is the longest prayer recorded in the New Testament and the longest prayer of Jesus given to us. We have many sermons, parables and conversations of Jesus but few recorded prayers. Often in the Gospels we are told that he is in the act of prayer but we are not told (except when he prays in Gethsemane, see Matthew 26: 39) what the content of his 'intercessions' were. Thus, there is something unique in John 17. The prayer marks the end of Jesus' earthly ministry and looks forward to the spread of the gospel throughout the world by the apostles and their successors.