One thousand ... - The sense of this is, that you shall be easily alarmed and overcome by those who are inferior in numbers and strength. The number 'one thousand,' is put for a large indefinite number; probably meaning all.

At the rebuke of one - The number one here is put to denote a very small number; a number in the ordinary course of warfare entirely disproportionate to those who would be vanquished. There is probably a reference here to the prediction in Deuteronomy 32:30 :

How should one chase a thousand,

And two put ten thousand to flight,

Except their Rock had sold them

And Yahweh had shut them up?

At the rebuke of five - Of a very small number.

Till ye be left as a beacon upon the top of a mountain - The word rendered 'beacon' (תרן toren), (Greek ἱστὸς histos, "a mast"), denotes properly the mast of a ship Isaiah 33:23; Ezekiel 27:5; then anything resembling a mast, a flagstaff, or a beacon of any kind. It may refer to a staff or mast erected on a promontory to warn sailors, or to be a landmark - as it is not improbable that the masts of ships would be employed for that purpose; or it may refer to a flagstaff, erected on a conspicuous place, to which the nation could rally in time of war. On the sea coasts of America such beacons are often erected. Those which I have seen consist of a pole erected on an eminence or rising ground, with a cask or barrel painted white on the top. The idea seems to be, that of a long pole erected for any purpose, and which was standing alone, stripped of its leaves and branches, and without ornament. So would be the few, solitary, and scattered Jews when driven before their enemies.

And as an ensign on a hill - (see Isaiah 5:26, note; Isaiah 11:12, note). The idea is, that those who should escape would be few in number, and would stand alone, as a beacon in view of all the nations, to admonish them of the justice of God, and the truth of his threatening - like an ensign floating on a hill that can be seen from afar. What a striking description is this of the condition of the Jews in our times, and indeed in all ages since their dispersion! Their strength, and influence, and power as a people are gone. They stand as beacons to warn the nations of the evils of a want of confidence in God, and of his justice.

At the rebuke of five shall ye flee "At the rebuke of five, ten thousand of you shall flee" - In the second line of this verse a word is manifestly omitted, which should answer to one thousand in the first: the Septuagint supply πολλοι, רבים rabbim. But the true word is רבבה rebabah, as I am persuaded any one will be convinced, who will compare the following passages with this place: -

"How should one chase a thousand;

And two put ten thousand (רבבה) to flight?"

One thousand shall flee at the rebuke of one,.... A troop of horse, consisting of a thousand men, shall flee upon the attack and onset of a single person, so dispirited should they be, and so possessed of the fear of the enemy; what was promised to them with respect to their enemies is here turned against them, Leviticus 26:7,

at the rebuke of five shall ye flee; being attacked by a very small number, the whole army should run away: this denotes with what ease they should be routed, and put to flight; and is to be understood, not of what would be at the present time, but of what should come to pass hereafter, when the Chaldean army should come against them;

till ye be left as a beacon upon the top of a mountain; or, "as the mast of a ship", so the Septuagint and other versions. Jarchi says it signifies a high tree, or tall piece of wood fixed in the earth, like a ship's mast (p), set up to give warning of an enemy's approach, and when, and where, sometimes fires used to be kindled; hence the Targum is,

"till ye are left as a burning torch on the top of a mountain.''

The Syriac version renders it, "as a wild ass", solitary and alone:

and as an ensign on a hill; erected as a trophy of victory. The design of the metaphors is to show that there should be few that should escape falling into the enemy's hand, here and there one, that should he scattered about, and be very thin, as beacons and signs are, and should be warnings to others of pursuing the same foolish and sinful methods and practices.

(p) So Ben Melech says, it is a high piece of wood in a ship, on which they hang an ensign or flag; and so he interprets the ensign in the next clause of a veil, so called, because they lift it up upon the mast.

One thousand shall flee at the rebuke of one; at the rebuke of five shall ye flee: till ye be left as a beacon upon the {p} top of a mountain, and as an ensign on an hill.

(p) Whereas all the trees are cut down save two or three to make masts.

30:17 'Till - 'Till you be destroyed, and but a few of you left.

a beacon: or, a tree bereft of branches, or, boughs: or, a mast

17. One thousand-A thousand at once, or, "As one man" [Maurer].

rebuke-the battle cry.

shall ye-at the rebuke of five shall ye, namely, all (in contrast to the "one thousand") flee so utterly that even two shall not be left together, but each one shall be as solitary "as a signal staff" [G. V. Smith], or "a banner on a hill" (Isa 5:26; 11:12). The signal staff was erected to rally a nation in war. The remnant of Jews left would be beacons to warn all men of the justice of God, and the truth of His threatenings. Gesenius (from Le 26:8; De 32:30) arbitrarily inserts "ten thousand." "At the rebuke of five shall ten thousand of you flee."

30:8-18 The Jews were the only professing people God then had in the world, yet many among them were rebellious. They had the light, but they loved darkness rather. The prophets checked them in their sinful pursuits, so that they could not proceed without fear; this they took amiss. But faithful ministers will not be driven from seeking to awaken sinners. God is the Holy One of Israel, and so they shall find him. They did not like to hear of his holy commandments and his hatred of sin; they desired that they might no more be reminded of these things. But as they despised the word of God, their sins undermined their safety. Their state would be dashed in pieces like a potter's vessel. Let us return from our evil ways, and settle in the way of duty; that is the way to be saved. Would we be strengthened, it must be in quietness and in confidence, keeping peace in our own minds, and relying upon God. They think themselves wiser than God; but the project by which they thought to save themselves was their ruin. Only here and there one shall escape, as a warning to others. If men will not repent, turn to God, and seek happiness in his favour and service, their desires will but hasten their ruin. Those who make God alone their confidence, will have comfort. God ever waits to be gracious to all that come to him by faith in Christ, and happy are those who wait for him.