Deuteronomy 29:23
And that the whole land thereof is brimstone, and salt, and burning, that it is not sown, nor beareth, nor any grass groweth therein, like the overthrow of Sodom, and Gomorrah, Admah, and Zeboim, which the LORD overthrew in his anger, and in his wrath:
The verse stands in the part of Deuteronomy that renews the covenant and sets out solemn warnings of fearful curses and judgments for disobedience and transgression. It places the devastation within those curses for disobedience and the judgments that came upon Israel, with the land made barren, covered with brimstone, salt, and burning, bearing no crops or grass, after the pattern of the overthrow of Sodom, Gomorrah, Admah, and Zeboim.
The words are not a description of Israel's condition in Moses' day but the speech of onlookers in a future time when God casts Israel out for its sins. Nations and strangers from a far land then witness the punishment and see the plagues and sicknesses laid on the land, and ask why such wrath has fallen on it. That desolation comes because Israel forsook the covenant the Lord made with their fathers when He brought them out of Egypt.
The picture is of complete desolation: the whole land becomes brimstone, salt, and burning, not sown, bearing nothing, with no grass growing, left barren and ruined by the Lord's anger and wrath, like the overthrow of Sodom, Gomorrah, Admah, and Zeboim. That description matches the land around the Dead Sea as it now lies, more desolate than the great desert. The brimstone is the masses of bitumen thrown up from the bottom, the salt is the salt waters and the salt pillar, the burning is the seared earth, fetid exhalations, leafless wastes and brazen sky, and the unsown, unproductive ground is the dead land as well as the dead sea. The Jordan has no outlet, with a deep basin about thirteen hundred feet deep where the river bed once lay and a shallow plain about thirteen feet deep where the cities of the plain formerly stood, and this awful desolation, viewed with its history in the light of the Bible, stands as a solemn witness to the truth of the Scriptural account.
The sentence was applied as a prophetic warning fulfilled in the later desolation of Galilee, presenting that ruined and barren condition as the fulfillment of the warning. It also foretold the days of vengeance upon Israel for neglected opportunities and unperformed duties and final rejection of Christ, fulfilled in the desolation of Jerusalem. It was literally fulfilled because the warning that blood defiles the land and the land cannot be cleansed except by the blood of the one who shed it was unheeded, continuing the curse first laid on the soil when Cain shed blood.
What the vengeance of eternal fire did to Sodom and Gomorrah shows the meaning and end of such fire: its office is to consume and destroy whatever it can affect, leaving the whole land desolate with burning brimstone and salt where nothing is sown or grows. Applied to future punishment, this proves that everlasting fire ends in utter consumption, so that the penalty of God's law for personal disobedience is literal death. The four named cities stand as monuments and examples of wickedness, corruption, vice, and social decay overwhelmed by judgment, and in the present time nearly every city approaches or nearly equals them in corruption and crime.