The Lord's most mysterious, organic speaking to the disciples is in John 14 through 16. This took place in the night when He was betrayed and arrested, before His crucifixion, which happened the next day. After His long discourse of mysterious speaking, He offered a prayer to God, saying, "Father,...glorify Your Son that the Son may glorify You" (John 17:1). Then He went on to pray about the oneness of the believers.
John 14 through 17 reveals the organism of the processed and consummated Triune God and the believers' oneness incorporated with the oneness of the Triune God. Two onenesses are incorporated into one. An organism, like a tree, is a frame to contain the inner life for the development of that inner life. The church, composed of God's called ones, is such a frame to contain the invisible God as life so that this life can be developed and expressed. Our human body is an organism containing our human life for the development and expression of that life. The Body of Christ is just like our human body. It is an organism to contain God, not the original God, but the processed and consummated God as life.
John 14 through 16 is a long discourse given by Christ to His disciples on the night before He was crucified concerning the issue of His glorification by the Father with His glory. Without Christ's glorification, these three chapters could not exist.
In the New Testament, there are two major portions which speak of the Divine Trinity clearly and definitely. The first one is Matthew 28:19, where the Lord charged us to baptize people into the name (singular) of the Father and of the Son and of the Spirit. There is one name for the three of the Trinity. The second passage is in John 14. In Matthew, it is the Triune God in name. But in John 14, it is the Triune God in person.
In John 14:16-20 Jesus said that He would ask the Father to give the disciples another Comforter, who would be the Spirit of reality coming to be with them and in them. Then He said, "In that day you will know that I am in My Father, and you in Me, and I in you" (v. 20). The speaking here is simple, but the content is very mysterious and excellent. The Lord's asking the Father to give the disciples another Comforter implies that He was the first Comforter. The two Comforters are one person in different stages. The first Comforter was Christ in the flesh in the stage of His incarnation. He comforted His disciples, but this comforting was outside of them. The Lord walked, lived, and ate together with the disciples. He was among them and with them, but He was not yet in them and they were not in Him. The Spirit was not yet at that time (John 7:39). In His resurrection He became the second Comforter in the stage of Christ as the life-giving Spirit, the stage of His inclusion. On the day of resurrection, Christ was glorified to be the life-giving Spirit (1 Cor. 15:45b). As the life-giving Spirit He could be in the disciples and they could be in Him.