Assur also is joined with them - Assyria. Assyria was on the northeast of Palestine. The conspirators had secured, it seems, the aid of this powerful kingdom, and they felt confident of success.
They have holpen the children of Lot - The sons, or the descendants of Lot. The margin is, as the Hebrew, "been an arm to." That is, they were an aid, or help; in other words, the sons of Lot were permitted, as it were, to make use of the arm of these powerful nations in accomplishing their purposes. The sons of Lot were Moab and Ammon, the ancestors of the Moabites and the Ammonites, Genesis 19:37-38. It would appear from this, that the purpose of destroying the Hebrew people had been originated by the Moabites and Ammonites, and that they had called in the aid of the surrounding nations to enable them to carry out their plan. The enumeration of those who had joined in the alliance shows that all the nations adjacent to Palestine, on every side, had entered into the agreement, so that the land was completely encompassed, or hemmed in, by enemies. In these circumstances, the conspirators felt secure; in these circumstances, the Hebrew people had no resource but to call upon God. Thus it often occurs that the people of God are so surrounded by enemies, or are so hemmed in by troubles and trials, that they have no other resource than this: they are shut up to the necessity of prayer. Often God so orders, or permits things to occur, as to cut off his people from every other dependence, and to make them feel that there is no help for them but in Him.

Asser also is joined - The Ammonites might have got those auxiliaries from beyond the Euphrates, against Jehosphaphat, as formerly they were brought against David. See 2-Samuel 10:16.
They have holpen the children of Lot - The Ammonites, who appear to have been the chief instigators in this war.

Assur also is joined with them: they have holpen the children (g) of Lot. Selah.
(g) The wickedness of the Ammonites and Moabites is described in that they provoked these other nations to fight against the Israelites.

Assur also is joined with them,.... Before mentioned, or Assyria, though at so great a distance from Israel, and unprovoked by them: according to R. Joseph Kimchi, the sense is, that the Assyrians joined them, continuing in their wickedness, though their army had been destroyed by an angel in Hezekiah's time, of which they were unmindful; but this, as his son observes, makes this confederacy and war to be after the times of Hezekiah; whereas it was long before it: the Targum is,
"Sennacherib, king of Syria, is joined with them;''
and so some refer this to his invasion of Judea, and besieging Jerusalem, with an army consisting of many nations, in Hezekiah's time; but he was the principal there, and not an auxiliary, as here:
they have holpen the children of Lot; or were "an arm" (h) unto them, assisted and strengthened them: these were the Moabites and Ammonites, who were the principals in the war, and the rest auxiliaries, as it appears they were in the times of Jehoshaphat, 2-Chronicles 20:1, here were ten different nations, which joined in confederacy against the people of Israel; to which answer the ten horns of the beast, or ten antichristian kings, who agreed to give their kingdom to the beast, and to make war with the Lamb and his followers, Revelation 17:12, and it may be observed, that these were on all sides of the land of Israel; the Edomites, Ishmaelites, and Amalekites, were on the south; the Moabites, Ammonites, and Hagarenes, were on the east; the Assyrians on the north; and the Philistines, Gebalites, and Tyrians, on the west: so that Israel was surrounded on all sides with enemies, as the Lord's people are troubled on every side, 2-Corinthians 4:8, and so the Gog and Magog army, of which some understand this, will encompass the camp of the saints about, and the beloved city, Revelation 20:9.
Selah. See Gill on Psalm 3:2.
(h) "fuerunt brachium", Pagniuus, Montanus; "sunt brachium", Junius & Tremellius, Piscator, &c.

Of Lot - Moab and Ammon.