Did Christ die for our unbelief if He indeed died for us ? The answer is Yes, for thats the primary sin of the World Jn 1:29 that constitued us as sinners in the first place Rom 5:19 19 For as by one man's disobedience[unbelief] many were made sinners, so by the obedience of one shall many be made righteous. It was an evil heart of unbelief that departed from the Living God Heb 3:12 12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God. This evil is described in Isa 53:6 6 All we like sheep have gone astray; we have turned every one to his own way; and the Lord hath laid on him the iniquity of us all. It was the sin of going astray, and this means , made to err, having been seduced or deceived: Remember how Paul wrote about what satan did to Eve 2 Cor 11:3 3 But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ. Eves sin was the actual Transgression 1 Tim 2:14 14 And Adam was not deceived, but the woman being deceived was in the transgression. So the going astray out of the right way, was merely a symptom of a evil heart of unbelief, departing from the Living God; But notice must be taken, the Prophet stated that this Iniquity of us all was laid upon Christ, Isa 53:6 6 All we like sheep have gone astray; we have turned every one to his own way; and the Lord hath laid on him the iniquity of us all. That iniquity of us all was our going astray with an evil heart of unbelief , departing from the living God Heb 3:12,13 12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God. 13 But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin. Yet Christ died for it, He had to since the iniquity of it was laid upon Him by the Lord God: The conclusion therefore is if any whom He died for go to hell for their sins in unbelief as Per Jn 8:24, then they are being punished Twice for their evil heart of unbelief, once in their Surety Shepherd and now again in themselves, which makes God unjust, and also makes Christ death for them of no avail, because their sin of unbelief still condemnard them to hell ! The Death of Christ heals our backsliding Hos 14:4 I will heal their backsliding, I will love them freely: for mine anger is turned away from him. What turned away Gods anger and or wrath ? It was the Blood of Christ ! 1 Pet 2:24 24 Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed. Unbelief in the Elect has been healed, forgiven for Christ's Sake !