The Prophet proceeds with the same subject, nor ought it to be deemed a useless prolixity. It would have indeed been sufficient by one word to threaten the Israelites, had they been pliable and obedient; but as they were stupid in their perverseness, it was necessary to stun their ears with continual threatening, that they might be at least less excusable before God. Hence the Prophet says now, that the king of Samaria shall be cut off like the foam: and he thus speaks of the king, because the Israelites thought their king, next to their idols, to be to them an invincible fortress. For thus ungodly men, as it has been mentioned before, always imagine their stronghold to be in the world and earthly things. Hence, the Lord denounces a just punishment, by saying that he would cut off the king; for the impious confidence, of which I have spoken, could not be otherwise corrected. Therefore "the king of Samaria shall be cut off" -- in what manner? "Like a foam". It is a most apt comparison; for the Prophet shows that the condition of the kingdom, which they imagined to be firm and perpetual, had nothing in it but an empty appearance, like the foam, which has nothing substantial. And further, he seems to me to point out another thing, that is, that the kingdom, though it showed itself to be above other kingdoms, was yet but an excrement. The foam floats above the waters of the sea, and by its height seems eminent; but what is the foam but the excrement of the water? for whatever is decayed in the waters passes into foam. So Israel thought, that as they were endued with power, and in every way excelled the tribe of Judah, they could ride, as it were, over their heads. The Prophet, on the contrary, says that they were foam, and also their king. "Your king," he says, "though the king of Judah cannot be compared with him, is yet a foam. By his height he seems indeed wonderful, and hence has arisen your pride, for you are now become hardened against God; but the Lord will cut him off like a foam." The Prophet then not only compares the king of Israel to a bubble or to foaming waters; but he says, that with respect to the king of Judah, he is an excrement. We now then understand the meaning of the Prophet.

Her king is cut off like foam - (Or, more probably, "a straw) on the" (literally, "face of the) water." A bubble, or one of those little shreds which float in countless numbers on the surface of the water, give the same image of lightness, emptiness, worthlessness, a thing too light to sink, but driven impetuously, and unresistingly, here and there, at the impulse of the torrent which hurries it along. Such was the king, whom Israel had set in the highest place, in whom it had trusted, instead of God. So easily was Hoshea, their last king, swept away by the flood, which broke in on Ephraim, from Assyria. Piety is the only solidity; apart from piety all is emptiness.

Her king is cut off as the foam - As lightly as a puff of wind blows off the foam that is formed below by a fall of water, so shall the kings of Israel be cut off. We have already seen that not less than four of them died by assassination in a very short time. See on Hosea 7:7 (note).

As for Samaria,.... The metropolis of the ten tribes of Israel, and here put for the whole kingdom:
her king is cut off; which some understand of Pekah, who was killed by Hoshea; others of several of their kings cut off one after another, very suddenly and quickly, as the metaphor after used shows; or rather Hoshea the last king is meant, who was cut off by the king of Assyria; the present tense is used for the future, to denote the certainty of it. Aben Ezra thinks the verb "cut off" is to be repeated, Samaria is "cut off, her king is cut off"; both king and kingdom destroyed. So the Targum,
"Samaria is cut off with her king:''
as the foam upon the water; as any light thing flowing upon it; as the bark of a tree, as Kimchi and Abarbinel; or as the scum upon a boiling pot of water, as Jarchi, and the Targum; or as foam, which is an assemblage of bubbles upon the water; such are kings and kingdoms, swell, look big and high for a while; but are mere bubbles, empty things; and are often suddenly, quickly, and easily destroyed; so Samaria and her king were by the Assyrian army; the Lord of hosts, the King of kings, being against them.

(Hosea 10:3, Hosea 10:15).
foam--denoting short-lived existence and speedy dissolution. As the foam, though seeming to be eminent raised on the top of the water, yet has no solidity, such is the throne of Samaria. MAURER translates, "a chip" or broken branch that cannot resist the current.

With the carrying away of the golden calf the kingdom of Samaria also perishes, and desert plants will grow upon the places of idols. Hosea 10:7, Hosea 10:8. "Destroyed is Samaria; her king like a splinter on the surface of the water. And destroyed are the high places of Aven, the sin of Israel: thorn and thistle will rise up on their altars; and they will speak to the mountains, Cover us! and to the hills, Fall on us!" שׁמרון מלכּהּ is not an asyndeton, "Samaria and its king;" but Shōmerōn is to be taken absolutely, "as for Samaria," although, as a matter of fact, not only Samaria, the capital of the kingdom, but the kingdom itself, was destroyed. For malkâh does not refer to any particular king, but is used in a general sense for "the king that Samaria had," so that the destruction of the monarchy is here predicted (cf. Hosea 10:15). The idea that the words refer to one particular king, is not only at variance with the context, which contains no allusion to any one historical occurrence, but does not suit the simile: like a splinter upon the surface of the water, which is carried away by the current, and vanishes without leaving a trace behind. Qetseph is not "foam" (Chald., Symm., Rabb.), but a broken branch, a fagot or a splinter, as qetsâphâh in Joel 1:7 clearly shows. Bâmōth 'âven are the buildings connected with the image-worship at Bethel ('âven = Bēth-'ēl, Hosea 10:5), the temple erected there (bēth bâmōth), together with the altar, possibly also including other illegal places of sacrifice there, which constituted the chief sin of the kingdom of Israel. These were to be so utterly destroyed, that thorns and thistles would grow upon the ruined altars (cf. Genesis 3:18). "The sign of extreme solitude, that there are not even the walls left, or any traces of the buildings" (Jerome). When the kingdom shall be thus broken up, together with the monarchy and the sacred places, the inhabitants, in their hopeless despair, will long for swift death and destruction. Saying to the mountains, "Cover us," etc., implies much more than hiding themselves in the holes and clefts of the rocks (Isaiah 2:19, Isaiah 2:21). It expresses the desire to be buried under the falling mountains and hills, that they may no longer have to bear the pains and terrors of the judgment. In this sense are the words transferred by Christ, in Luke 23:30, to the calamities attending the destruction of Jerusalem, and in Revelation 6:16 to the terrors of the last judgment.

Is cut off - Shortly will be cut off: this prophecy probably was delivered when Samaria was besieged.