Jesus repeats what He had said earlier to the religious leaders (John 7:33-34, 8:14). He has told them that if anyone follows Him, they will walk in light, but if they refuse, they will walk in darkness. The Jews were expecting a type of Messiah who wasn’t coming. When they would search for the Messiah, they would fail to find Him, because Jesus, who was the Messiah, would have been and gone.
He adds the ominous phrase, “you will die in your sins”, which will happen if they do not believe that Jesus is who He says He is. When they try and get Him to clarify, He says that it has been obvious what He has been declaring from the beginning. That is, He is the Messiah, the Son of God, the Savior of the Jews, and of the world. He is God. They knew He was claiming that; it is why they were trying to have Him killed (John 5:18, 10:31-33).
Jesus was speaking the true things God the Father had given Him to say. The Pharisees did not comprehend Him because they were not born again from God (John 3:3). They would miss their opportunity, as do all who finally reject the Lord (John 14:6 / Acts 4:12 / 1 Timothy 2:5 / Hebrews 9:27). This is the unyielding truth of God’s Word.
There is a sense in which people seek God but don’t find Him because they’re not seeking the real God (the Jesus of the Bible), in the real way (repentance and faith). Instead, they chase after a figment of their imagination, a projection of their best feelings. They refuse to look where He really is, or live the way He really wants. Many say that they love, serve, and seek God; but their idea of God is not real.
Many call themselves Christian, and think they are right with God, but they are not (Matthew 7:21-23). If we continue in sin, refuse to repent, and refuse God’s wisdom, eventually our cries will not be heard (cf. Psalm 66:18 / Proverbs 1:28-31 / Isaiah 1:15 / Amos 8:11-12 / Micah 3:4). Turn to Jesus today, whoever you are.