John 8:24

I said therefore unto you
Because they were from beneath, and of the world, and discovered an earthly, worldly, carnal, yea, devilish disposition, in their conduct towards him:

that ye shall die in your sins;
this he had said in ( John 8:21 ) , and now repeats it, and confirms it by the following reason:

for if believe not that I am he;
the everlasting and unchangeable I am, the true God, God over all, blessed for ever; the eternal Son of God, God manifest in the flesh, really made flesh, and become incarnate; the true Messiah, the only Saviour of sinners; the one and only Mediator between God and man; the Head of the church, prophet, priest, and King, and the Judge of quick and dead; as also the light of the world he had declared himself to be: these are things that are necessary to be believed concerning Christ; indeed, carnal and unregenerate men may believe all these things; the devils themselves do, and tremble at them; but then they, and so unconverted men, have no faith in them, with an application of them to themselves: true faith in Christ deals not with him in a general way, but in a special regard to a man's self; it is a seeing of Christ for a man's self; it is not an implicit faith, or a believing him to be what he is, merely upon report, but upon sight; it is a going out of the soul to Christ, a renouncing its own righteousness, and a trusting in him alone for life and salvation; it is with the heart, and from it, and is unfeigned; it works by love to Christ, and his people, and is attended with the fruits of righteousness, and a cheerful obedience to the commands and ordinances of Christ. Though perhaps no more than a general faith is here intended, for want of which, and their rejection of Jesus, as the Messiah, the Jews suffered temporal ruin; and had they but believed that Jesus was the Son of God, and true Messiah, they had been saved from that temporal destruction which came upon their nation, city, and temple; but not believing this in a general and notional, way, they perished, as is here threatened:

ye shall die in your sins;
in which they were, being defiled with them, guilty before God for them, under the power of them, and liable to punishment for them; and so they remained, and did remain, and were yet in their sins, even until death, when they died in them, and for them, not only a corporeal, but an eternal death: for dying in their sins, these would be found upon them, and they would be charged with them, and must be answerable for them, and consequently endure the punishment of them, which is the second death. Dying in sin, and dying in Christ, are two widely different things. They that die in faith, die in Christ: they that die in unbelief, die in sin; and this is a dreadful dying; see ( Joshua 22:20 ) , where the Targum paraphrases it, "and he, one man", (or alone,) (hybwxb) (twm al) , "did not die in his sins".