John 4:25-26 ESV
25 The woman said to him, “I know that Messiah is coming (he who is called Christ). When he comes, he will tell us all things.”
26 Jesus said to her, “I who speak to you am he.”
I AM He. Was, is, and is to be. He is all things for He is the beginning and the end.
So He told us.
εἰμί * eimi * i-mee' * First person singular present indicative; a prolonged form of a primary and defective verb; I exist (used only when emphatic): - am, have been, X it is I, was.