Let burning coals fall upon them - Let them be punished, "as if" burning coals were poured upon them. See Psalm 11:6, note; Psalm 18:12-13, notes; Psalm 120:4, note.
Let them be cast into the fire - Punished as if they were cast into the fire and consumed.
Into deep pits, that they rise not up again - That they may utterly perish. This was one mode of punishing, by casting a man into a deep pit from which he could not escape, and leaving him to die, Genesis 37:20, Genesis 37:24; Psalm 9:15; Psalm 35:7; Jeremiah 41:7.

Let burning coals - The Chaldee considers this as spoken against Ahithophel, who was head of a conspiracy against David; and translates this verse thus: "Let coals from heaven fall upon them, precipitate them into the fire of hell, and into miry pits, from which they shall not have a resurrection to eternal life." This is a proof that the Jews did believe in a resurrection of the body, and an eternal life for that body, in the case of the righteous.

Let burning coals fall upon them: (h) let them be cast into the fire; into deep pits, that they rise not up again.
(h) That is by God, for David saw that they were reprobate and that there was no hope of repentance in them.

Let burning coals fall upon them,.... From heaven, as the Targum, Aben Ezra, and Kimchi, by way of explanation; alluding to the burning of Sodom and Gomorrah with fire from thence: and may design both the terrible judgments of God in this life, and everlasting burnings in hell; so Jarchi interprets it of the coals of hell; see Psalm 11:6;
let them be cast into the fire; into the fire of divine wrath, and have severe punishment inflicted on them in this world; and into the fire of hell hereafter, as the Targum, which is unquenchable and everlasting; and into which all wicked men, carnal professors, the followers of antichrist, the devil and his angels, will be cast: of the phrase of casting into hell, see Matthew 5:29;
into deep pits, that they rise not up again; meaning either the grave, the pit of corruption; from whence the wicked will not rise to eternal life, as the Targum adds, for though they will rise again, it will be to everlasting shame and damnation, Daniel 12:2; or else the pit of hell, the bottomless pit, from whence there will be no deliverance; where they must lie till the uttermost farthing is paid, and that will be for ever. Arama refers this to Korah, who was burnt and swallowed up, and rose not again in Israel.

(Compare Psalm 11:6; Psalm 120:4).
cast into the fire; into deep pits--figures for utter destruction.

Coals - Divine vengeance, which is compared to coals of fire.