John 8:24 (NKJV)
“Therefore I said to you that you will die in your sins; for if you do not believe that I am He, you will die in your sins."
Let's go back a few verses to start and continue reading through the full context of this portion of scripture.
John 8:21-30 (NKJV)
Then Jesus said to them again, “I am going away, and you will seek Me, and will die in your sin. Where I go you cannot come.” So the Jews said, “Will He kill Himself, because He says, ‘Where I go you cannot come’?” And He said to them, “You are from beneath; I am from above. You are of this world; I am not of this world. Therefore I said to you that you will die in your sins; for if you do not believe that I am He, you will die in your sins.” Then they said to Him, “Who are You?” And Jesus said to them, “Just what I have been saying to you from the beginning. I have many things to say and to judge concerning you, but He who sent Me is true; and I speak to the world those things which I heard from Him.” They did not understand that He spoke to them of the Father. Then Jesus said to them, “When you lift up the Son of Man, then you will know that I am He, and that I do nothing of Myself; but as My Father taught Me, I speak these things. And He who sent Me is with Me. The Father has not left Me alone, for I always do those things that please Him.” As He spoke these words, many believed in Him.”
Now the statement Jesus spoke in verse 21 is very similar to what He spoke in verse 34 of chapter 7. “You will seek Me and not find Me, and where I am you cannot come”.
Israel was longing and looking for the Messiah, which has continued even after their rejection and His crucifixion. Vainly they have expected the great Prince foretold in their Scriptures; and bitter has been their disappointment, from age to age, because he does not appear. Sadly they continue to cling to their false hope of who the Messiah should be, and hardening themselves against the evidence that He has already appeared in the person as Jesus of Nazareth, they will never find the deliverer whom they seek.
“Where I go you cannot come” means that men who reject the Son of God can never come into God's presence while rejecting the Lord Jesus. He is the only way to the Father; and men shall come to God through Christ, or they will not come to God at all.
Now we see Jesus add a firm warning this time “you will die in your sin” in verse 21 and He then again says it twice in today's verse 24. This tells us the reason why the Pharisees would be unable to go where Jesus was going. Only the pure, the forgiven, and the redeemed will follow the Lord there. They were self righteous, full of pride and denying the Son of God as He stood in their midst!
This is yet another affirmation that forgiveness of sins is possible only for those who believe in the Lord Jesus Christ. Refusal to believe in Him is loss of eternal life. Jesus is the means of salvation. It was the war cry of the early church that "There is none other name under heaven given among men" wherein we must be saved.
Friends, no other system, philosophy, ethics, morals, good works, or anything else can provide any hope for eternal life apart from Jesus Christ. Everlasting life is "in Him"; it cannot be found anywhere else!