He is the light of the world. You must follow Him. His Father (God) sent Him. You don't know God if you don't follow Him. You'll die in your sins unforgiven, unless you believe in Him. Following Him means knowing the truth, which will set you free.
They naturally ask who He is and where His Father is, not realizing He means God. Their national pride gets in the way, thinking they aren't slaves, as sons of Abraham.
Now Jesus ups the ante. You're trying to kill Me, because you are of your father the devil, not of Abraham. If you knew God, you would love Me. I'm speaking God's Words, but you don't listen and you reject Me because you don't know Him. Name any sin you've seen in Me. If you keep My Word, you won't die. Before Abraham was, I AM. (Exodus 3:14 - "And God said to Moses, “I AM WHO I AM.” And He said, “Thus you shall say to the children of Israel, ‘I AM has sent me to you.’”)
Their response: you have a demon! You think You're greater than Abraham? You aren't even 50! They try to stone Him, but He hides somehow, and leaves.
Texts like this prove C.S. Lewis' point that Jesus was either a liar, a lunatic, or the Lord. We can't take Him as a good moral teacher without accepting Him as God. He didn't just tell us how to live and live well Himself. We have to follow and obey Him, or we're doomed.