John 8:25-28

So they said to Him, “Who are You [anyway]?” Jesus replied, “What have I been saying to you from the beginning? I have many things to say and judge concerning you, but He who sent Me is true; and I say to the world [only] the things that I have heard from Him.” They did not realize [or have the spiritual insight to understand] that He was speaking to them about the Father. So Jesus said, “When you lift up the Son of Man [on the cross], you will know then [without any doubt] that I am He, and that I do nothing on My own authority, but I say these things just as My Father taught Me.