Then the Lord rained—literally, and Jehovah caused it to rain; καὶ κύριος ἔβρεξε (LXX.), which latter term is adopted by Luke in describing this event (Genesis 17:1-27:29)—upon Sodom and upon Gomorrah—and also upon Admah and Zeboim (Deuteronomy 29:23; Hosea 11:8), Bela, or Zoar, of the five cities of the Jordan circle (Genesis 14:2, Genesis 14:8) being exempted—brimstone and fire— גָּפְרִית; properly pitch, though the name was afterwards transferred to other inflammable materials (Gesenius); וָאֵשׁ, and fire, which, though sometimes used of lightning, as in 1 Kings 18:38; 2 Kings 1:10, 2 Kings 1:12, 2 Kings 1:14; Job 1:16, may here describe a different sort of igneous agency.
Whether this Divinely-sent rain was "burning pitch" (Keil), of lightning which ignited the bituminous soil (Clericus), or a volcanic eruption which overwhelmed all the region (Lynch, Kitto), it was clearly miraculous in its nature, and designed as a solemn punitive infliction on the cities of the plain—from the Lord—i.
e. Jehovah (the Son) rained down from Jehovah (the Father), as if suggesting a distinction of persons in the Godhead; otherwise the phrase is regarded as "an elegancy of speech" (Aben Ezra), "an emphatic repetition" (Calvin), a more exact characterization of the storm (Clericus, Rosenmüller) as being out of heaven.