When we read Jn 3:18 18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God. We read of them being condemned already, and for that to be True, such ones Christ could not have died for, because God in Justice cannot and will not condemned anyone, any sinner for whom Christ died, simply because Christ has already been condemned for them, having had their sins and condemnation charged to Him. Where Rom 5:18 states that condemnation came upon all by one Adam Rom 5:18 18 Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life. Well, that Judgment unto condemnation came upon Christ instead of them, because He was their Surety ! So now that Justice for them has been served, God would be unjust to have anyone Christ died for under the sentence of condemnation at anytime, that would be equivalent to our double jeopardy laws !