12" “I still have many things to say to you, but you cannot bear them now.13 When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come. 14 He will glorify me, for he will take what is mine and declare it to you. 15 All that the Father has is mine; therefore I said that he will take what is mine and declare it to you."
John 16:12-15
The immediate context of our Lord's next statement about the Spirit (13) is what He says in 12 about the disciples not being able to bear all that He could tell them at that time. This means, for one thing, that there were some truths that Jesus could not communicate to the disciples till after the cross and resurrection and ascension. These mighty acts had to be accomplished before real understanding could come to them. For another thing, it underlines the essential unity of the New Testament writings, and asserts their inspiration. For what He implies is that the 'many things' (12) which He could not then teach them He would teach them afterwards by His Spirit, and these things are embodied in the New Testament epistles written by the apostles under the guidance and inspiration of the Holy Spirit. Propositions therefore emerge here; firstly, the epistles are Christ's teaching to the Church; and secondly, the writers of the epistles wrote under the same inspiration as Himself, for, in both cases, the Spirit of God was the Inspirer. The epistles are therefore just as authoritative as the actual words of Jesus. These are very important propositions, for they show that the teaching of the apostles is an extension of His own teaching, a development of it, a logical and spiritual outcome of what He had said, and an authoritative interpretation of what He had done on the cross. It is the continuing work of revelation by the Spirit that our Lord has in mind. This does not mean that we can assume that the Spirit will ever continue to reveal new truth; there is a givenness about the Biblical revelation that is complete within the historical canon of Scripture in the sense that there is no more to be revealed. And all new or further revelation now can be nothing more than the elucidation or illumination of what has already been given once and for all in Scripture. The Spirit is the great Interpreter of the Word.