Albert Barnes Commentary Deuteronomy 29:23

"[and that] the whole land thereof is brimstone, and salt, [and] a burning, [that] it is not sown, nor beareth, nor any grass groweth therein, like the overthrow of Sodom and Gomorrah, Admah and Zeboiim, which Jehovah overthrew in his anger, and in his wrath:" — Deuteronomy 29:23 (ASV)

The description is borrowed from the local features of the Dead Sea and its vicinity. The towns of the Vale of Siddim were fertile and well-watered until devastated by the wrath of God (Genesis 19:24–25). The ruin of Israel and its land should be of a similar kind (Psalms 107:34; Zephaniah 2:9). The desolate state of Palestine at present, and the traces of former fertility and prosperity, are attested by every traveler.