I have spoken these things in "paroimia". (Jn 16:25)
The word can be translated, proverbs figure of speech, veiled speech, enigmatic speech.
He is going back to the Father and when he comes back it will all be clear and our joy will be complete. But in the meantime, we must live with the paroimia.
The great temptation is for us to try and turn his language, and in fact the many forms of speech in the bible into direct speech. Some people take it all literally: from creation in Genesis being 7 calendar day, to 144,000 being the number saved because Revelation says so. The other extreme are those who remove all historical content so that even the resurrection for them is a symbolic thing. As usual both extremes miss the mark. The Bible does contain some history but it is a theology book.
Why couldn't Jesus have spoken mor plainly? He couldn't because we have no point of reference. Jesus was trying to decribe for us the world as God sees it, the Kingdom of God which we will only see in the next life. He is the second person of the trinity, he has come from the Father and is going back from whence he came. He has been there. He has seen it.
Jesus spoke concretely when he could. He gives plenty of direct commands: love God, love your neighbor, go and teach all nations, do not be afraid...
But whenever he ventures beyond the mundane, there are no words. How can he or St. Paul describe fully the effects of baptism? What words can fully capture the Eucharist? Describe heaven, hell, purgatory, angels. Even the concept of eternal is beyond our experience.
For as smart as we like to think we are, the vast majority of the universe is beyond our comprehension in this life. The up side is that we can constantly read the words of Jesus, and in fact most of the Bible, over and over again and never tire, because as we grow in faith, hope, and love we are able to comprehend ever more deeply, looking forward to that day when we will in the Kingdom, see as God sees.
