It is your unhappiness, that while I am alive, and preaching the gospel to you, inviting you to repentance, and faith in me, as the true Messiah, you will not believe me to be indeed what I am; but you shall lift me up upon the cross, (for that is meant by lifting up, as 1 Thessalonians 3:14, 1 Thessalonians 12:32), and when that time cometh, you shall know that I am the light of the world, as 1 Thessalonians 8:12; for after that, the gospel began to be preached to all nations: or, that I am the true Messiah, he whom the Father hath sent into the world. Some of you shall then know it by those signs and wonders that shall attend my death and resurrection, and to your shame and confusion: others of you shall know it to your eternal joy and salvation; believing on me then, whom you will not now acknowledge; and that what I have done, I have only done by commission from my Father, not of myself; and that what I have taught, I have had in commission from my Father to teach.
Related Commentaries of John 8:28
John 8:28
28 Then said Jesus unto them,When ye have lifted up the Son of man, then shall ye know that I am he, and that I do nothing of myself; but as my Father hath taught me, I speak these things.