The Punishment of Sin is Eternal
Meditate for awhile, O devout soul, on the eternity of future punishment, and you will perceive more clearly its awful severity. The flames of hell rage and burn without end, forever and ever. The life of the lost is to die eternally; their death is to live in everlasting torment. The devil never wearies in tormenting the lost, nor will death ever come to their relief. That fire is always consuming that it may always keep alive; those torments are ever increasing that they may always be renewed; the lost are ever dying that they may always live; and they ever live that they may always keep on dying!
That one is to be tormented forever and ever, without any cessation whatsoever, will sink the soul in the deepest despair. What can be more intolerable than to be always longing for that which can never be realized, and to be longing for that to end which never can end? In that eternal world, the lost will never obtain that which they so ardently desire, and yet they will be compelled to suffer what they most abhor, forever and ever.
When the holy wrath of God against sin shall cease, then shall cease the punishment of the damned; but that wrath is eternal, and so will their punishment be. When the lost exercise true repentance, then can they be delivered from their sins; but the time for repentance has passed, and no hope of divine pardon remains. When devils cease to torment, the lost will cease to be tormented; but the hellish rage of the devil never will cease, and neither then will the torments of the lost. When God's eternal justice changes, the punishment of the damned will cease; but God never can cease to be just, and so their torments shall continue forever and ever.
It is but strict justice that those who would never leave off sinning in this life shall never leave off suffering for it there. It is but right that vengeance shall never terminate upon that soul which, while it could, never desired to terminate its career of sin. The damned spent their own eternity, that is, this earthly life, in persistent sin; and it is just and right that they should spend God's eternity in suffering for their sin. They ceased to sin only because they ceased to live; nor would they have shown any desire to cease sinning could they have prolonged their lives eternally, that they might sin eternally.
The fuel of the fires of hell—that is, the spots and stains of sin—is eternal; and so shall its punishment deservedly be. God's eyes will never be closed to the awful heinousness of sin in the condemned soul; how then can the dread penalty pronounced against sin ever be relaxed? Sin is an infinite offence, because it is committed against an infinite God; and Christ has paid for its satisfaction an infinite price, and it is but right therefore that those who willfully die in sin should suffer an infinite penalty for it.
Man by his sin has destroyed the eternal good that was in him; and so by the just and impartial judgment of God he suffers eternal evil. God in the beginning created man in His own image that he might live in blessedness with Him forever; and has renewed him after his fall into sin in the image of Christ. He has prepared for all the means of eternal salvation, and offered to all its great rewards; it is no more than just that those who have despised these rewards so offered should be subjected to eternal punishment. The will to do evil shall never be taken from the lost, nor the punishment of that will ever cease. They foolishly preferred the fleeting pleasures and short-lived good of this world to God, the infinite Good; their aspirations were all for the delights of this brief and transitory life rather than for the unspeakable treasures of eternal life; and it is but just that they shall suffer the punishments of doom eternal.
O boundless eternity! O immeasurable eternity! O eternity that baffles the grasp of finite mind; how your illimitable ages will add to the torments of the damned! After the lapse of unnumbered ages the thought will still come with crushing force that this is but the beginning of their endless torment. What a severe affliction we esteem it here for an invalid to lie, unable to move, even upon the softest couch, for so brief a time as thirty years; but, oh, what will it be to lie burning in that "lake which burneth with fire and brimstone" (Revelation 21:8) for thirty thousands of thousands of years!
O eternity, eternity, how you alone immeasurably heighten the torments of the damned! Severe indeed is their punishment on account of the bitter pain of the torments they shall suffer; severer still because of the diversity of these torments; but the thought that they shall last forever and ever with no diminution or cessation is the worst of all. That will be death without death, end without end, perishing without perishing; because that death is an ever living death; that end is a ceaseless beginning; and that perishing knows no perishing. Those poor lost souls shall seek for life and find it not; they "shall desire to die, and death shall flee from them" (Revelation 9:6); and after a hundred billion years they shall simply suffer renewed torments without end! The very thought of the endlessness of their pain will torment them more than the sense of eternal pain itself. What can be conceived of as more intolerable than thus to die that you are always living, and thus to live that you are always dying? That life will be lifeless, and that death will be deathless! If you are life, why do you die, and if death, how do you always endure?
Our minds cannot grasp the idea of eternity; as it can be circumscribed by no measure of time, so it can be comprehended by no finite mind. If you would get some conception of eternal duration, think of time before the creation of the world. If you can find a point of time when God had a beginning, you can determine also when the sufferings of the lost will end.
Imagine a mountain whose lofty height exceeds the distance from earth to the sky; suppose an eagle should carry away from this mountain a single grain of the finest sand once in a thousand years, now we might conceive that after an incomprehensibly long period of ages the task might be finished and the mountain entirely removed; and yet we cannot hope that the fires of hell will ever be extinguished. The rewards of the saved will never come to an end, and neither will the punishments of the lost; for as God's mercy toward the elect is infinite, so will be His justice towards the reprobate.
Suppose that the torments of the lost in kind are as numerous as the drops of the ocean. Now suppose that at the end of every thousand years a little bird should fly down and drink a tiny drop of water from that vast ocean. We might hope that by and by the waters of that ocean would be exhausted; but we cannot hope that the torments of the damned will ever, ever come to an end.
O devout soul, let the eternity of future punishment be ever before your mind; to remember hell thus may prevent your falling into it at last. Take heed that you repent, while yet the time of pardon lingers! What shall that fire consume but your sins? And the more you heap up iniquities, the more fuel you are laying up for those eternal burnings.
O blessed Lord Jesus, who have offered complete satisfaction for our sins by Your bitter passion, guard us from eternal condemnation at the last! Amen.
Edited from Johann Gerhard's Sacred Meditations (Philadelphia, PA: Lutheran Publication Society, 1896), Meditation #50.