I know where I CAME from but you have no idea where I COME from

[tonychanyt]

John 8:

14 Jesus answered, "Even if I testify on my own behalf, my testimony is valid, for I know where I came [aorist] from and where I am going. But you have no idea where I come [present indicative] from or where I am going.

Why did Jesus change the past tense to the present tense?

The aorist "came" indicates the one-time incarnation event: from heaven to human.

The present indicative "come" indicates a continuing present event: the words of God from heaven keep coming to Jesus.

Even in English today, when someone says something strange, one may react with "Where is that come from?".

A similar usage is in John 3:

31 The one who comes from above is above all; the one who is from the earth belongs to the earth, and speaks as one from the earth. The one who comes from heaven is above all.

The context bears this out, John 8:

13 The Pharisees challenged him, “Here you are, appearing as your own witness; your testimony is not valid.”
14Jesus answered, “Even if I testify on my own behalf, my testimony is valid, for I know where I came from and where I am going. But you have no idea where I come from or where I am going. 15You judge by human standards; I pass judgment on no one. 16But if I do judge, my decisions are true, because I am not alone. I stand with the Father, who sent me. 17In your own Law it is written that the testimony of two witnesses is true. 18I am one who testifies for myself; my other witness is the Father, who sent me.”

Jesus is saying that his words and acts are continuously coming from the Father. That is why the present indicative "come" is used. It is not a one-time event.

 

[Diamond72]

I stand with the Father, who sent me. 17In your own Law it is written that the testimony of two witnesses is true. 18I am one who testifies for myself; my other witness is the Father, who sent me.”

That was then. Now the Holy Spirit has been given so the Holy Spirit and God the Father give testimony.