A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
isa 18:1(Isa 18:1-7)
Woe--The heading in English Version, "God will destroy the Ethiopians," is a mistake arising from the wrong rendering "Woe," whereas the Hebrew does not express a threat, but is an appeal calling attention (Isa 55:1; Zac 2:6): "Ho." He is not speaking against but to the Ethiopians, calling on them to hear his prophetical announcement as to the destruction of their enemies.
shadowing with wings--rather, "land of the winged bark"; that is, "barks with wing-like sails, answering to vessels of bulrushes" in Isa 18:2; the word "rivers," in the parallelism, also favors it; so the Septuagint and Chaldee [EWALD]. "Land of the clanging sound of wings," that is, armies, as in Isa 8:8; the rendering "bark," or "ship," is rather dubious [MAURER]. The armies referred to are those of Tirhakah, advancing to meet the Assyrians (Isa 37:9). In English Version, "shadowing" means protecting--stretching out its wings to defend a feeble people, namely, the Hebrews [VITRINGA]. The Hebrew for "wings" is the same as for the idol Cneph, which was represented in temple sculptures with wings (Psa 91:4).
beyond--Meroe, the island between the "rivers" Nile and Astaboras is meant, famed for its commerce, and perhaps the seat of the Ethiopian government, hence addressed here as representing the whole empire: remains of temples are still found, and the name of "Tirhakah" in the inscriptions. This island region was probably the chief part of Queen Candace's kingdom (Act 8:27). For "beyond" others translate less literally "which borderest on."
Ethiopia--literally, "Cush." HORSLEY is probably right that the ultimate and fullest reference of the prophecy is to the restoration of the Jews in the Holy Land through the instrumentality of some distant people skilled in navigation (Isa 18:2; Isa 60:9-10; Psa 45:15; Psa 68:31; Zep 3:10). PhÅnician voyagers coasting along would speak of all Western remote lands as "beyond" the Nile's mouths. "Cush," too, has a wide sense, being applied not only to Ethiopia, but Arabia-Deserta and Felix, and along the Persian Gulf, as far as the Tigris (Gen 2:13).
isa 18:2ambassadors--messengers sent to Jerusalem at the time that negotiations passed between Tirhakah and Hezekiah against the expected attack of Sennacherib (Isa 37:9).
by . . . sea--on the Nile (Isa 19:5): as what follows proves.
vessels of bulrushes--light canoes, formed of papyrus, daubed over with pitch: so the "ark" in which Moses was exposed (Exo 2:3).
Go--Isaiah tells them to take back the tidings of what God is about to do (Isa 18:4) against the common enemy of both Judah and Ethiopia.
scattered and peeled--rather, "strong and energetic" [MAURER]. The Hebrew for "strong" is literally, "drawn out" (Margin; Psa 36:10; Ecc 2:3). "Energetic," literally, "sharp" (Hab 1:8, Margin; the verb means to "sharpen" a sword, Eze 21:15-16); also "polished." As HERODOTUS (3:20, 114) characterizes the Ethiopians as "the tallest and fairest of men," G. V. SMITH translates, "tall and comely"; literally, "extended" (Isa 45:14, "men of stature") and polished (the Ethiopians had "smooth, glossy skins"). In English Version the reference is to the Jews, scattered outcasts, and loaded with indignity (literally, "having their hair torn off," HORSLEY).
terrible--the Ethiopians famed for warlike prowess [ROSENMULLER]. The Jews who, because of God's plague, made others to fear the like (Deu 28:37). Rather, "awfully remarkable" [HORSLEY]. God puts the "terror" of His people into the surrounding nations at the first (Exo 23:27; Jos 2:9); so it shall be again in the latter days (Zac 12:2-3).
from . . . beginning hitherto--so English Version rightly. But GESENIUS, "to the terrible nation (of upper Egypt) and further beyond" (to the Ethiopians, properly so called).
meted out--Hebrew, "of line." The measuring-line was used in destroying buildings (Isa 34:11; Kg2 21:13; Lam 2:8). Hence, actively, it means here "a people meting out,--an all-destroying people"; which suits the context better than "meted," passively [MAURER]. HORSLEY, understanding it of the Jews, translates it, "Expecting, expecting (in a continual attitude of expectation of Messiah) and trampled under foot"; a graphic picture of them. Most translate, of strength, strength (from a root, to brace the sinews), that is, a most powerful people.
trodden down--true of the Jews. But MAURER translates it actively, a people "treading under foot" all its enemies, that is, victorious (Isa 14:25), namely, the Ethiopians.
spoiled--"cut up." The Nile is formed by the junction of many streams in Abyssinia, the Atbara, the Astapus or Blue river (between which two rivers Meroe, the "Ethiopia" here meant, lies), and the Astaboras or White river; these streams wash down the soil along their banks in the "land" of Upper Egypt and deposit it on that of Lower Egypt. G. V. SMITH translates it, "Divide." HORSLEY takes it figuratively of the conquering armies which have often "spoiled" Judea.
isa 18:3see ye . . . hear ye--rather, "ye shall see . . . shall hear." Call to the whole earth to be witnesses of what Jehovah ("He") is about to do. He will "lift up an ensign," calling the Assyrian motley hosts together (Isa 5:26) on "the mountains" round Jerusalem, to their own destruction. This (the eighteenth chapter) declares the coming overthrow of those armies whose presence is announced in Isa 17:12-13. The same motive, which led Hezekiah to seek aid from Egypt, led him to accept gladly the Ethiopian Tirhakah's aid (Isa 36:6; Isa 37:9). Ethiopia, Egypt, and Judea were probably leagued together against the common enemy, 713 B.C. See notes on the twenty-second chapter, where a difference of tone (as referring to a different period) as to Ethiopia is observable. HORSLEY takes the "ensign" to be the cross, and the "trumpet" the Gospel trumpet, which shall be sounded more loudly in the last days.
isa 18:4take . . . rest . . . consider--I will calmly look on and not interpose, while all seems to promise success to the enemy; when figuratively, "the sun's heat" and "the night dews" ripen their "harvest"; but "before" it reaches its maturity I will destroy it (Isa 18:5; Ecc 8:11-12).
like a clear heat--rather, "at the time of the clear (serene) heat" [MAURER].
upon herbs--answering to "harvest" in the parallel clause. MAURER translates, "in the sunlight" (Job 31:26; Job 37:21; Hab 3:4).
like . . . dew--rather, "at the time of the dew cloud." God's "silence" is mistaken by the ungodly for consent; His delay in taking vengeance for forgetfulness (Psa 50:21); so it shall be before the vengeance which in the last day shall usher in the restoration of the Jews (Isa 34:1-8; Isa 57:11, end of the verse, Pe2 3:3-10).
isa 18:5For--rather, "But."
perfect--perfected. When the enemy's plans are on the verge of completion.
sour grape . . . flower--rather, "when the flower shall become the ripening grape" [MAURER].
sprigs--the shoots with the grapes on them. God will not only disconcert their present plans, but prevent them forming any future ones. HORSLEY takes the "harvest" and vintage here as referring to purifying judgments which cause the excision of the ungodly from the earth, and the placing of the faithful in a state of peace on the earth: not the last judgment (Joh 15:2; Rev 14:15-20).
isa 18:6birds . . . beasts--transition from the image "sprigs," "branches," to the thing meant: the Assyrian soldiers and leaders shall be the prey of birds and beasts, the whole year through, "winter" and "summer," so numerous shall be their carcasses. HORSLEY translates the Hebrew which is singular: "upon it," not "upon them"; the "it" refers to God's "dwelling-place" (Isa 18:4) in the Holy Land, which Antichrist ("the bird of prey" with the "beasts," his rebel hosts) is to possess himself of, and where he is to perish.
isa 18:7present . . . people scattered and peeled--For the right rendering, see on Isa 18:2. The repetition of epithets enhances the honor paid to Jehovah by so mighty a nation. The Ethiopians, wonder-struck at such an interposition of Jehovah in behalf of His people, shall send gifts to Jerusalem in His honor (Isa 16:1; Psa 68:31; Psa 72:10). Thus translate: "a present . . . from a people." Or translate, as English Version; "the present" will mean "the people" of Ethiopia converted to God (Rom 15:16). HORSLEY takes the people converted to Jehovah, as the Jews in the latter days.
place of the name--where Jehovah peculiarly manifests His glory; Act 2:10 and Act 8:27 show how worshippers came up to Jerusalem from Egypt" and "Ethiopia." Frumentius, an Egyptian, in the fourth century, converted Abyssinia to Christianity; and a Christian church, under an abuna or bishop, still flourishes there. The full accomplishment is probably still future.
The nineteenth and twentieth chapters are connected, but with an interval between. Egypt had been held by an Ethiopian dynasty, Sabacho, Sevechus, or Sabacho II, and Tirhakah, for forty or fifty years. Sevechus (called So, the ally of Hoshea, Kg2 17:4), retired from Lower Egypt on account of the resistance of the priests; and perhaps also, as the Assyrians threatened Lower Egypt. On his withdrawal, Sethos, one of the priestly caste, became supreme, having Tanis ("Zoan") or else Memphis as his capital, 718 B.C.; while the Ethiopians retained Upper Egypt, with Thebes as its capital, under Tirhakah. A third native dynasty was at Sais, in the west of Lower Egypt; to this at a later period belonged Psammetichus, the first who admitted Greeks into Egypt and its armies; he was one of the dodecarchy, a number of petty kings between whom Egypt was divided, and by aid of foreign auxiliaries overcame the rest, 670 B.C. To the divisions at this last time, GESENIUS refers Isa 19:2; and Psammetichus, Isa 19:4, "a cruel lord." The dissensions of the ruling castes are certainly referred to. But the time referred to is much earlier than that of Psammetichus. In Isa 19:1, the invasion of Egypt is represented as caused by "the Lord"; and in Isa 19:17, "Judah" is spoken of as "a terror to Egypt," which it could hardly have been by itself. Probably, therefore, the Assyrian invasion of Egypt under Sargon, when Judah was the ally of Assyria, and Hezekiah had not yet refused tribute as he did in the beginning of Sennacherib's reign, is meant. That Assyria was in Isaiah's mind appears from the way in which it is joined with Israel and Egypt in the worship of Jehovah (Isa 19:24-25). Thus the dissensions referred to (Isa 19:2) allude to the time of the withdrawal of the Ethiopians from Lower Egypt, probably not without a struggle, especially with the priestly caste; also to the time when Sethos usurped the throne and entered on the contest with the military caste, by the aid of the town populations: when the Saitic dynasty was another cause of division. Sargon's reign was between 722-715 B.C. answering to 718 B.C., when Sethos usurped his throne [G. V. SMITH].