They do not only justly deserve to be cast down thither, but the sentence of the law of God, that eternal and immutable rule of righteousness that God has fixed between him and mankind, is gone out against them, and stands against them; so that they are bound over already to hell. John iii. 18. "He that believeth not is condemned already." So that every unconverted man properly belongs to hell; that is his place; from thence he is, John viii. 23. "Ye are from beneath." And thither be is bound; it is the place that justice, and God's word, and the sentence of his unchangeable law assign to him.
------------------------------------------------------
Unconverted men walk over the pit of hell on a rotten covering, and there are innumerable places in this covering so weak that they will not bear their weight, and these places are not seen.
------------------------------------------------------
The use of this awful subject may be for awakening unconverted persons in this congregation. This that you have heard is the case of every one of you that are out of Christ.-That world of misery, that lake of burning brimstone, is extended abroad under you. There is the dreadful pit of the glowing flames of the wrath of God; there is hell's wide gaping mouth open; and you have nothing to stand upon, nor any thing to take hold of, there is nothing between you and hell but the air; it is only the power and mere pleasure of God that holds you up.
http://www.ldbc.net/sinners.htm